Calculator methods you can inspect

Charging cost = miles x kWh per 100 miles / 100 x electricity price / (1 - charging loss)

Use your actual vehicle efficiency and electricity rate for a useful estimate.

Accessed July 13, 2026

The general relationship between vehicle energy use and electricity price was checked on July 13, 2026. No live tariff, vehicle telemetry, or brand-specific rate is embedded.

Tesla and other EV drivers comparing trip or monthly charging-cost scenarios from vehicle efficiency, electricity price, and charging loss.

This is an energy-cost estimate, not a charger quote, utility bill, vehicle range prediction, charging-speed forecast, or brand-specific charging recommendation.

Use the actual EV's kWh per 100 miles, the applicable home or public charging price, and a reasonable charging-loss estimate. Weather, driving conditions, fees, idle charges, and time-varying tariffs can change actual cost.

APR is the annualized rate that makes the payment stream equal the net amount received after fees

This calculator uses an iterative present-value estimate for fixed monthly payments.

Last reviewed January 30, 2024

The CFPB distinction between interest rate and APR was checked on July 13, 2026. No lender pricing or current market rate is embedded in the calculator.

Borrowers comparing fixed-payment loan scenarios from a loan amount, upfront fees, monthly payment, and whole-month term.

This numerical estimate is not a lender's Truth in Lending disclosure, loan offer, legal determination of finance charges, or substitute for the APR in the signed agreement.

The estimate assumes the entered fees are deducted upfront, payments are equal and monthly, and the term is expressed in whole months. Different fee treatment, payment timing, or irregular cash flows can change APR.

Future value = principal x (1 + r)^n + monthly contribution x (((1 + r)^n - 1) / r), where r is monthly return and n is months

This calculator assumes monthly compounding, steady end-of-month contributions, and a constant annual return.

Current calculator; accessed July 13, 2026

Investor.gov's compound-interest inputs were checked on July 13, 2026. The Toolkit Shelf method uses a fixed monthly-compounding convention rather than live product rates.

People comparing long-term savings or investment scenarios from a starting amount, monthly contribution, assumed annual return, and time period.

This is a constant-return projection, not a forecast, guaranteed return, account statement, security recommendation, or substitute for investment and tax advice.

The result assumes a constant annual return compounded monthly and equal end-of-month contributions. It does not model volatility, taxes, fees, inflation, missed contributions, or changing returns.

Interest = average daily balance x (APR / 365) x days in billing cycle

Actual issuers may calculate balances and grace periods differently, so use statements for official numbers.

Last reviewed January 22, 2024

The CFPB explanation of daily periodic rates and average daily balances was checked on July 13, 2026. The calculator does not fetch issuer terms or account data.

Cardholders estimating one billing cycle's interest from an already calculated average daily balance, APR, cycle length, and payment.

This is not an issuer statement, payoff quote, grace-period determination, or reconstruction of transactions, fees, multiple APR balances, and the issuer's exact daily-balance method.

The entered balance must represent the cycle's average daily balance and the APR must apply to that balance. The estimate assumes APR divided by 365 and excludes new transactions, fees, grace periods, and multiple rate buckets.

Back-end DTI = total monthly debt payments / gross monthly income x 100

Front-end DTI uses housing payment only. Back-end DTI includes housing plus other recurring monthly debt payments.

Last reviewed August 28, 2023

The CFPB debt-to-income definition and formula were checked on July 13, 2026. No lender-specific limits or current credit policy are embedded.

Consumers making a planning estimate of front-end and back-end debt-to-income ratios from gross monthly income and recurring monthly debt payments.

The ratios are not a lender underwriting decision, approval threshold, credit assessment, affordability recommendation, or substitute for the debts and income definitions a lender applies.

Use gross monthly income and include every recurring monthly debt payment relevant to the comparison. Omissions, variable income, lender adjustments, and different housing-payment definitions can materially change the ratio.

Monthly payment = principal x monthly rate / (1 - (1 + monthly rate)^-months)

Extra payments are applied after the required amortized payment to estimate faster payoff and interest savings.

Last reviewed May 28, 2024

The CFPB explanation of fixed-payment amortization was checked on July 13, 2026. No current lender rate or product term is fetched.

Borrowers comparing fixed-rate installment-loan payments, payoff time, total interest, and an optional constant extra monthly payment.

This is not a lender quote, payoff statement, loan agreement, refinancing recommendation, or calculation of variable rates, fees, penalties, or lender-specific payment allocation.

The calculation assumes a fixed annual rate, monthly compounding, equal scheduled payments, and any extra amount applied monthly to principal. Fees, day-count conventions, payment dates, and variable rates are excluded.

Affordable payment = min(gross monthly income x housing limit, gross monthly income x total debt limit - monthly debts); affordable price = loan amount from the remaining principal-and-interest budget + down payment

The calculator subtracts estimated monthly property taxes, homeowners or mortgage insurance, and HOA dues before estimating a loan amount from the remaining principal-and-interest budget.

Current guide; accessed July 13, 2026

The CFPB guidance on total monthly housing costs and maintaining a budget cushion was checked on July 13, 2026. Users supply the rate, costs, and debt-ratio limits.

Prospective homebuyers testing a housing-budget scenario from income, debts, down payment, rate, term, ownership costs, and self-selected debt-ratio limits.

This is not mortgage preapproval, lender underwriting, a property valuation, an interest-rate quote, or a recommendation that the maximum estimated price is affordable for the household.

The estimate assumes the entered gross income, debts, down payment, fixed rate, term, taxes, insurance, HOA, and front-end and back-end limits are complete. PMI, closing costs, maintenance, reserves, and lender adjustments are not automatically added.

Monthly mortgage payment = amortized principal-and-interest payment + property tax / 12 + monthly insurance + monthly HOA

The calculator also estimates total interest from the principal-and-interest payment over the selected loan term.

Current worksheet; accessed July 13, 2026

The CFPB monthly-payment components were checked on July 13, 2026. The calculator uses only user-entered values and does not fetch rates, taxes, insurance, or HOA data.

Homebuyers and owners estimating a fixed-rate monthly mortgage payment and amortization from price, down payment, rate, term, taxes, insurance, and HOA dues.

This is not a lender quote, official loan estimate, approval decision, escrow statement, payoff amount, or complete ownership budget.

The loan uses a fixed annual rate and equal monthly payments. Property tax, insurance, and HOA remain constant; PMI, closing costs, maintenance, utilities, rate changes, and lender-specific escrow adjustments are excluded unless entered elsewhere.

Cost difference = estimated owner net cost - estimated rent cost

Owner net cost equals down payment, closing costs, and ownership payments minus estimated equity after sale. Rent cost sums monthly rent with annual rent growth.

Current guide; accessed July 13, 2026

The CFPB guidance on total ownership costs and budget tradeoffs was checked on July 13, 2026. All market and cost assumptions remain user-entered scenarios.

People comparing a defined rent scenario with a defined home-purchase scenario over a chosen number of years.

The comparison is not a recommendation to rent or buy, a forecast of home value or rent, a lender decision, a tax analysis, or personalized financial advice.

The result assumes the entered fixed mortgage rate, stay period, ownership costs, rent growth, appreciation, closing costs, and selling costs. It excludes tax deductions, investment opportunity cost, PMI, major repairs, moving costs, and transaction timing differences.

Gross paycheck = annual gross pay / pay periods; take-home = gross x (1 - tax rate)

This is a rough estimate and does not replace payroll or tax withholding calculations.

Current estimator; accessed July 13, 2026

The IRS withholding-estimator scope was checked on July 13, 2026. Toolkit Shelf does not embed tax tables; the user supplies one estimated tax rate.

Hourly workers comparing a rough gross-pay and take-home scenario from regular hours, overtime hours, pay frequency, and a self-selected tax rate.

This is not payroll processing, a withholding calculation, a wage-law determination, a pay stub, or a substitute for employer payroll records and the IRS estimator.

The estimate assumes 52 identical workweeks, overtime paid at 1.5 times the entered hourly rate, and one effective tax rate applied to gross pay. It excludes benefit deductions, payroll-tax details, state and local rules, exemptions, bonuses, and irregular schedules.

Estimated tax = max(0, (income - deductions) x tax rate - credits)

This is a simplified planning estimate based on the tax rate you enter, not a full tax filing calculation.

Tax year 2026; accessed July 13, 2026

The IRS 2026 standard deduction amounts were checked on July 13, 2026. The calculator uses the single-filer amount only as its editable starting value, embeds no bracket table, and applies the rate entered by the user.

People testing a simplified annual tax scenario from income, deductions, one self-selected effective tax rate, credits, and withholding.

This is not a tax return, filing calculation, withholding instruction, bracket calculator, eligibility determination, or substitute for current tax forms and qualified tax advice.

The estimate subtracts entered deductions, applies one flat rate to the remainder, subtracts entered credits, and compares entered withholding. It does not model progressive brackets, filing status, payroll taxes, state or local tax, credit phaseouts, alternative taxes, or tax-year changes.

BMI = kg / meters^2; US equivalent = pounds / inches^2 x 703

BMI is a screening measure and does not directly measure body fat or health. The calculator supports US and metric inputs.

June 26, 2024

The CDC adult categories and screening limitations were checked on July 12, 2026. The internal method version changes only after a material formula or category change.

Adults age 20 and older who want a general BMI screening number from measured height and weight.

BMI is a screening estimate, not a diagnosis, body-fat measurement, treatment recommendation, or substitute for professional medical advice.

Use adult inputs, measured height and weight, and the displayed unit conversion. Children, pregnancy, athletes, and individual medical context need different interpretation.

BMR = 10 x weight kg + 6.25 x height cm - 5 x age + 5 for men or -161 for women

BMR is an estimate of resting energy needs before activity is added.

February 1990

The published Mifflin equation and its adult study population were checked on July 12, 2026. The equation is fixed unless the internal method version changes.

Adults seeking a general resting-energy estimate from age, height, weight, and the equation's male or female coefficient.

This is predicted resting energy expenditure, not indirect calorimetry, maintenance calories, medical nutrition therapy, or a personalized intake target.

Use adult measurements and the coefficient that matches the equation input. Illness, pregnancy, medications, body-composition extremes, and individual metabolism can materially change actual needs.

Men: 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76; women: 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387

The equation uses inches internally. Metric inputs are converted to inches before calculation, and tape estimates remain sensitive to measurement technique.

June 28, 2013

The exact published circumference equations were checked on July 12, 2026. The calculator preserves those inch-based equations after visible unit conversion and does not assert current service policy.

Adults using repeatable height, neck, waist, and where applicable hip measurements for a tape-based body-fat trend estimate.

This is a circumference-based estimate, not a clinical body-composition measurement, diagnosis, service-eligibility decision, or substitute for professional assessment.

Use consistent anatomical landmarks, posture, breathing, and tape tension. Implausible or nonpositive circumference differences are invalid; the displayed estimate is bounded to 2% through 75% for interface safety.

Maintenance calories = Mifflin-St Jeor BMR x activity multiplier

This is a planning estimate. Actual needs vary by body composition, health, and activity.

February 1990

The published resting-energy equation is fixed; the selected activity multiplier remains a visible Toolkit Shelf planning assumption.

Adults comparing general maintenance-calorie scenarios from age, height, weight, sex, and a broad activity assumption.

This is a planning estimate, not measured energy expenditure, medical nutrition therapy, or a personalized weight-change prescription.

The estimate assumes the entered measurements are accurate and the chosen activity level reasonably represents the usual routine. Individual needs can differ materially.

Estimated conception date = estimated due date - 266 days

This is an estimate. Conception timing can vary, and clinical dating may use ultrasound or other information.

May 2017; reaffirmed 2025

ACOG's due-date framework and clinical dating limitations were checked on July 12, 2026. The plus-or-minus three-day window is a visible Toolkit Shelf planning convention.

People making a rough conception-date estimate from an already established estimated due date.

The result is calendar back-calculation, not proof of conception, ovulation, intercourse, parentage, clinical gestational dating, or a fertile-window determination.

The entered due date must already be a reliable obstetric estimate. Ultrasound, assisted reproduction, irregular cycles, and clinician-assigned dating take precedence over this 266-day subtraction.

Due date = first day of last period + 280 days + cycle adjustment

This is a common estimate and does not replace ultrasound dating or medical care.

May 2017; reaffirmed 2025

ACOG Committee Opinion No. 700 and its reaffirmed status were checked on July 12, 2026.

People making a rough pregnancy due-date estimate from a known last menstrual period and average cycle length.

This is an LMP-based planning estimate, not clinical dating, prenatal care, an ultrasound interpretation, or a replacement for a clinician-assigned due date.

The estimate assumes the last menstrual period is known and uses the entered cycle adjustment. Assisted reproduction, irregular cycles, and ultrasound findings require clinical dating.

Weight in kg = BMI x height in meters^2; US equivalent = BMI x height in inches^2 / 703

This calculator supports pounds with feet/inches or kilograms with centimeters, using adult BMI 18.5 to 24.9 as a broad screening range.

June 26, 2024

The CDC adult BMI categories and screening limitations were checked on July 12, 2026. Toolkit Shelf derives the range by solving the BMI equation for weight.

Adults comparing a broad BMI-based weight range for a measured height, with current weight used only for context.

The displayed 18.5 through 24.9 BMI range is not an individualized ideal weight, diagnosis, treatment goal, or substitute for medical context.

Use for adults age 20 and older with an accurate height. Children, pregnancy, athletes, edema, muscle mass, age-related change, and medical history need different interpretation.

Protein grams = protein calories / 4; carb grams = carb calories / 4; fat grams = fat calories / 9

Protein and carbohydrates use about 4 calories per gram. Fat uses about 9 calories per gram.

January 2020

FDA's general 4-calorie protein, 4-calorie carbohydrate, and 9-calorie fat factors were checked on July 12, 2026. Special fibers, sugar alcohols, and other exceptions are outside this calculator.

Adults converting a self-selected daily calorie total and protein, carbohydrate, and fat percentages into gram amounts.

The arithmetic does not recommend a calorie target or macro ratio and is not medical nutrition therapy, a disease-specific diet, or an assessment of food quality.

The calorie input and percentages must reflect the user's chosen plan, and the percentages should total 100%. The general energy factors do not model every nutrient-label exception.

Gestational age = days since first day of last menstrual period / 7

A 40-week estimate is commonly counted from the first day of the last menstrual period.

May 2017; reaffirmed 2025

ACOG Committee Opinion No. 700 and its reaffirmed status were checked on July 12, 2026.

People making a rough gestational-age estimate from a known last menstrual period and chosen as-of date.

This is an LMP-based planning estimate, not clinical gestational dating, prenatal care, or a replacement for ultrasound and clinician review.

The estimate assumes the last menstrual period and as-of date are correct. Assisted reproduction, irregular cycles, and ultrasound findings require clinical interpretation.

Protein grams per day = body weight in kg x grams per kg target

The adult RDA baseline is 0.8 g/kg for healthy adults; active targets are planning estimates.

March 2016

The adult 0.8 g/kg reference baseline and sports-nutrition range containing the 1.2 and 1.6 presets were checked on July 12, 2026.

Healthy adults comparing a general 0.8 g/kg baseline with optional 1.2 or 1.6 g/kg active-planning scenarios.

The selected grams-per-kilogram value is a planning scenario, not a personalized requirement, supplement recommendation, treatment plan, or assessment of protein quality.

Use measured adult body weight and choose a scenario that fits the actual activity context. Pregnancy, kidney disease, illness, energy restriction, elite training, and other clinical needs require qualified guidance.

TDEE = Mifflin-St Jeor BMR x activity multiplier

Activity multipliers are planning estimates, so real-world tracking is still important.

February 1990

The Mifflin resting-energy equation was checked on July 12, 2026. Activity factors and 300-calorie scenarios are visible Toolkit Shelf heuristics, not part of the source paper.

Adults comparing general maintenance-calorie scenarios from a Mifflin resting-energy estimate and a broad activity category.

This is not measured total energy expenditure, medical nutrition therapy, or a personalized loss or gain prescription; the plus-or-minus 300 calorie scenarios are planning examples.

Use accurate adult measurements and an activity level that represents the usual week. Pregnancy, illness, medications, eating-disorder recovery, body-composition extremes, and changing activity require different guidance.

Estimated total water = reference adequate intake + exercise add-on + hot-weather add-on

Reference adequate intakes include water from both food and beverages.

2005

The National Academies total-water baselines and their variability limits were checked on July 12, 2026. Exercise, heat, and 80% beverage adjustments are Toolkit Shelf planning heuristics.

Generally healthy adults comparing total-water adequate-intake reference values with rough exercise and hot-weather planning add-ons.

This is not a hydration prescription, fluid-balance assessment, heat-safety plan, or substitute for thirst, symptoms, medical restrictions, and qualified guidance.

The baseline represents total water from food and beverages for generally healthy people. Climate, exertion, pregnancy, lactation, medications, kidney or heart conditions, and acute illness can change needs substantially.

Remaining characters = character limit - caption characters

The default is an editable 2,200-character planning threshold, not a verified current TikTok maximum. Confirm the current limit in the app before publishing.

User-confirmed TikTok in-app limit

Confirm at time of use

No volatile platform maximum is asserted. The threshold remains editable so users can match the current limit shown by TikTok at the time of posting.

Creators checking caption length against an editable planning threshold before publishing in TikTok.

The default 2,200-character value is a Toolkit Shelf planning threshold, not a verified current TikTok maximum, publishing guarantee, display-preview guarantee, or platform policy statement.

The count includes every character in the entered caption. Confirm the current TikTok limit and relevant app surface, then edit the threshold before relying on the remaining-character result.

Page signal report = guarded HTML fetch + redirect follow + title + canonical + meta robots + googlebot + X-Robots-Tag + og:url checks

The checker fetches one public HTML URL, follows up to 5 redirects, and blocks local, private, reserved, credentialed, and non-http destinations before each request.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report is a bounded static-HTML check, not a Google indexing verdict, rendered-DOM test, authenticated crawl, or substitute for Search Console URL Inspection.

The URL must be publicly reachable over HTTP or HTTPS. Results cover the fetched response, headers, and static HTML within redirect, timeout, and body-size limits.

Heading report = guarded HTML fetch + redirect follow + h1-h6 extraction + outline order + H1, duplicate, empty, and skipped-level checks

The checker fetches one public HTML URL, follows up to 5 redirects, and blocks local, private, reserved, credentialed, and non-http destinations before each request.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report checks heading markup in one fetched HTML response; it is not a rendered accessibility audit, content-quality verdict, or full-site crawl.

The public response must contain the relevant headings in static HTML. Client-rendered, authenticated, blocked, or truncated content may be absent.

Header report = guarded request + redirect follow + final response status + selected cache, content, indexing, and policy headers

The checker fetches one public URL, follows up to 5 redirects, and blocks local, private, reserved, credentialed, and non-http destinations before each request.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report describes one observed response and does not prove every region, edge cache, browser, request method, or authenticated state behaves the same way.

The URL must be publicly reachable over HTTP or HTTPS. Header values reflect the server response observed by the checker at that moment.

Image report = guarded HTML fetch + redirect follow + img tag extraction + alt, duplicate, decorative, dimension, srcset, loading, and decoding checks

The checker fetches one public HTML URL, follows up to 5 redirects, and blocks local, private, reserved, credentialed, and non-http destinations before each request.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report inventories image markup in one response; it cannot decide whether alt text is contextually useful or replace an accessibility review with assistive technology.

Images and alt attributes must exist in the fetched static HTML. Client-rendered, lazy-injected, authenticated, blocked, or truncated content may be absent.

Structured data report = guarded HTML fetch + redirect follow + application/ld+json extraction + JSON parse + @type and @graph summary

The checker fetches one public HTML URL, follows up to 5 redirects, and blocks local, private, reserved, credentialed, and non-http destinations before each request.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report parses JSON-LD syntax and visible types; it is not Google Rich Results eligibility, schema-policy approval, or a rendered-DOM validator.

JSON-LD must exist in the fetched static HTML and be valid JSON. Client-injected, authenticated, blocked, or truncated markup may be absent.

Share preview report = guarded HTML fetch + redirect follow + title + meta description + Open Graph tags + Twitter Card tags + preview image checks

The checker fetches one public HTML URL, follows up to 5 redirects, and blocks local, private, reserved, credentialed, and non-http destinations before each request.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report reads static Open Graph and card metadata; it cannot reproduce every platform cache, crop, scraper user agent, or JavaScript-rendered preview.

Preview tags must exist in the fetched static HTML. Platform caches, client rendering, authentication, blocking, and truncation can change real previews.

Link report = guarded HTML fetch + redirect follow + anchor tag extraction + href classification + anchor text and rel attribute checks

The checker fetches one public HTML URL, follows up to 5 redirects, and blocks local, private, reserved, credentialed, and non-http destinations before each request.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report inventories one page response and does not replace a rendered interaction test, full crawl, link-status audit, or editorial review of anchor meaning.

Links must appear in the fetched static HTML. Client-rendered, authenticated, blocked, or truncated links may be absent from the result.

Redirect report = guarded HEAD request + manual Location following + final status + hop timing + unsafe-destination blocks

The checker blocks localhost, private IPs, reserved IPs, credentialed URLs, and non-http destinations before each request and after each redirect.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report shows one server-side redirect path, not every browser, geography, user agent, cookie state, cache layer, or authenticated flow.

The URL must be publicly reachable over HTTP or HTTPS. The checker blocks private destinations and follows at most five redirects with bounded timeouts.

Discovery report = guarded origin check + /robots.txt fetch + /sitemap.xml fetch + Sitemap declarations + User-agent * Disallow summary + sitemap loc count

The checker only fetches conventional robots.txt and sitemap.xml URLs for one public origin. It does not crawl the site or simulate a search engine bot.

User-provided public URL

At each run

Each result is a point-in-time server request. Rerun the checker after the page, server, cache, or redirect behavior changes.

Site owners, developers, editors, and launch reviewers checking one public URL at a time.

The report checks conventional root files and basic directives; it is not a search-engine crawl verdict, complete robots parser, sitemap submission, or index-coverage report.

The origin, /robots.txt, and /sitemap.xml must be publicly reachable. Results are bounded by redirect, timeout, and response-size limits.

Password = Web Crypto random selections from the enabled character sets, including at least one character from every enabled set

Selection uses rejection sampling to avoid modulo bias. The displayed entropy is an approximate search-space estimate and is not a security guarantee.

Accessed July 13, 2026

The browser Web Crypto API and current NIST password guidance were checked on July 13, 2026. No external password database, server request, or live account policy is used.

People generating a unique random credential locally before storing it in a trusted password manager.

The generator supplies random text, not account protection, secure storage, breach monitoring, phishing resistance, recovery, multi-factor authentication, or a guarantee that a destination accepts the selected characters.

Use a browser with crypto.getRandomValues, select at least one character set, confirm the destination's password rules, keep the result unique, and store it securely. The entropy number is an approximate alphabet-size model rather than a security guarantee.