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Appliance Wattage Calculator

Use this appliance wattage calculator to estimate what a device costs to run from its wattage and daily use.

Method and assumptions documentedFree toolSource note included

Live calculator

Appliance wattage

Monthly energy use72 kWh

2.4 kWh per day.

Monthly cost$12.96

At 18 cents per kWh.

Annual cost$155.52

Monthly cost multiplied by 12.

Wattage is power, kWh is energy

Watts show how much power an appliance draws while running. Electric bills charge for energy, so this calculator converts watts and hours into kilowatt-hours.

Appliance energy breakdown

Power multiplied by time and converted to kWh.

MeasureEstimate
Daily kWh2.4 kWh
Monthly kWh72 kWh
Daily cost$0.43
Monthly cost$12.96

Utility estimates depend on local rates, fixed fees, taxes, runtime, billing period, and household usage. Compare against the actual bill before settling up.

Quick answer

Appliance Wattage Calculator: what it calculates

Appliance Wattage Calculator calculates appliance energy cost from watts, quantity, hours per day, days per month, and electricity rate. The visible formula is kWh = watts x quantity x hours / 1000; cost = kWh x electricity rate.

ResultAppliance energy cost
InputsWatts, Quantity, Hours per day, Days per month, Electricity rate
FormulaAppliance wattage formula

Formula

Appliance wattage formula

kWh = watts x quantity x hours / 1000; cost = kWh x electricity rate

Actual use can be lower than nameplate wattage when appliances cycle on and off.

How to use

Steps

  1. Enter the wattage listed on the appliance label or product manual.
  2. Enter quantity if you run more than one of the same device.
  3. Enter hours per day and days per month.
  4. Enter your electricity rate in cents per kWh.

Example

Sample calculation

Watts1,200
Use2 hours/day for 30 days
Energy72 kWh/month
At 18 cents/kWh$12.96/month

Calculator use

Best for

  • Use this appliance wattage calculator to estimate what a device costs to run from its wattage and daily use.
  • Estimating home utility cost, shared bills, appliance usage, or service charges before splitting or budgeting.
  • Testing usage changes such as shorter showers, different appliance cycles, rate changes, or roommate shares.
  • Keeping rate, meter, usage, and fixed-fee assumptions visible before comparing against a real bill.

Before relying on it

Check first

  • Leaving out fixed service fees, tiered rates, taxes, delivery charges, minimum bills, seasonal rates, or billing-period length.
  • Using appliance labels, averages, or old bills without checking actual runtime, local rates, and household usage.
  • Splitting a bill without agreeing whether fixed fees, shared rooms, guests, or unequal usage should be weighted.

Details

What to know before using the result

WattsInstant power draw

Watts describe how much power the device uses while running at that setting.

Kilowatt-hoursPower over time

Electric bills use energy over time, so watts are multiplied by hours and divided by 1,000.

Cycling appliancesAverage draw may vary

Refrigerators, HVAC, dehumidifiers, chargers, and heaters may cycle or change power levels during use.

Source notes

References used for this calculator

U.S. Energy Information AdministrationExplains electricity prices per kilowatt-hour and why local household rates vary.U.S. Energy Information AdministrationExplains watts, watthours, and kilowatt-hours with examples of power used over time.

Benchmarks

How to read the result

Under 100W: Low draw.

Common for LED lights, chargers, fans, and efficient electronics.

500W - 1,500W: High draw.

Common for heaters, microwaves, hair dryers, kettles, and some kitchen appliances.

Runs daily: Cost compounds.

Even a modest wattage can matter if it runs for many hours every day.

Calculator accuracy

Methodology and assumptions

Formula

kWh = watts x quantity x hours / 1000; cost = kWh x electricity rate

Inputs used

Watts, Quantity, Hours per day, Days per month, Electricity rate

Limitations

Utility pages use visible usage and rate assumptions. Actual bills may include tiers, service fees, delivery charges, taxes, minimums, seasonal rates, and provider-specific rules.

Review record

Catalog QA baseline on June 6, 2026. This date marks the catalog-wide automated and editorial QA baseline, not a tool-specific expert review.

Cite this page

Toolkit Shelf. Appliance Wattage Calculator. https://toolkitshelf.com/tools/appliance-wattage-calculator

FAQ

Common questions

How do I convert watts to kWh?

Multiply watts by hours used, then divide by 1,000. For cost, multiply kWh by your electricity rate.

Where do I find appliance wattage?

Check the appliance label, manual, product page, or a plug-in energy meter. Some labels show amps and volts instead of watts.

Why is actual cost different?

Many devices cycle, change modes, or use less than rated wattage during normal operation. Utility rates and fees also vary.