Quick answer
Calorie Calculator: what it calculates
Calorie Calculator calculates maintenance calories from sex, age, weight, height, and activity level. The visible formula is Maintenance calories = Mifflin-St Jeor BMR x activity multiplier.
Health Calculators
Calorie Calculator
Use this calorie calculator to estimate maintenance calories, BMR, and simple daily targets for gradual weight loss or gain.
Method and assumptions documentedPlanning estimateSource note includedNo expert review claimed
Live calculator
Calorie calculator
Maintenance calories2,008 / day
Estimated calories to maintain current weight.
Weight loss target1,708 / day
A moderate estimate using about 300 calories below maintenance.
BMR1,460 / day
Basal metabolic rate estimate before activity adjustment.
Use this as a planning estimate, not medical advice. Medical conditions, medication, pregnancy, eating disorder history, or disease-specific nutrition needs should be handled with a qualified professional.
ResultMaintenance calories
InputsSex, Age, Weight, Height, Activity level
FormulaCalorie estimate formula
Formula
Calorie estimate formula
Maintenance calories = Mifflin-St Jeor BMR x activity multiplierThis is a planning estimate. Actual needs vary by body composition, health, and activity.
How to use
Steps
- Choose sex, age, height, and weight.
- Select the closest activity level.
- Read estimated maintenance calories.
- Use loss and gain targets as moderate planning estimates.
Example
Sample calculation
Profile35-year-old female
Height and weight5 ft 6 in, 165 lb
ActivityLight activity
Maintenance2,017 calories/day
Calculator use
Best for
- Estimating daily maintenance calories for general adult planning.
- Comparing how activity level, height, weight, age, and sex assumptions change the estimate.
- Setting a starting point for trend tracking before adjusting based on real weight and energy changes.
- Preparing a rough nutrition discussion with assumptions visible.
Before relying on it
Check first
- Treating a calorie estimate as medical nutrition advice.
- Ignoring medical conditions, medications, eating disorder history, pregnancy, lactation, or sport-specific needs.
- Changing intake aggressively from one calculator result without monitoring trends or professional guidance.
- Using stale weight, activity, or body-composition assumptions when your situation has changed.
Details
What to know before using the result
Estimate typeBMR x activity
The calculator estimates resting needs from body inputs, then applies an activity multiplier to approximate maintenance calories.
Activity sensitivityMultiplier matters
Small changes in selected activity level can move the result by hundreds of calories per day.
Adjustment loopTrack reality
Use the result as a starting target, then adjust from real weight, appetite, training, and health feedback over time.
Benchmarks
How to read the result
-300/day: Moderate deficit.
Often used as a gentler weight-loss planning target.
Maintenance: Stable weight.
Estimated calories to maintain current weight.
+300/day: Moderate surplus.
Often used for gradual weight gain planning.
Calculator accuracy
Methodology and assumptions
Formula
Maintenance calories = Mifflin-St Jeor BMR x activity multiplier
Inputs used
Sex, Age, Weight, Height, Activity level
Limitations
Health results are screening or planning estimates. Age, body composition, medication, medical history, pregnancy, and professional guidance can change the right interpretation.
Review record
Method and sources checked on July 12, 2026. The documented method, source timing, validity conditions, and reliance limits were checked on this date.
Method provenanceEstimate · toolkitshelf.calorie-mifflin-activity.v1
- Maintained by
- Toolkit Shelf
- Calculation class
- Estimate
- Method version
- toolkitshelf.calorie-mifflin-activity.v1
- Primary source
- Mifflin et al. resting-energy equation
- Source date
- February 1990
- Source checked
- July 12, 2026
- Intended audience
- Adults comparing general maintenance-calorie scenarios from age, height, weight, sex, and a broad activity assumption.
- Valid when
- The estimate assumes the entered measurements are accurate and the chosen activity level reasonably represents the usual routine. Individual needs can differ materially.
- Reliance boundary
- This is a planning estimate, not measured energy expenditure, medical nutrition therapy, or a personalized weight-change prescription.
- Data freshness
- The published resting-energy equation is fixed; the selected activity multiplier remains a visible Toolkit Shelf planning assumption.
Cite this page
Toolkit Shelf. Calorie Calculator. https://toolkitshelf.com/tools/calorie-calculator
FAQ
Common questions
How are maintenance calories calculated?
The calculator estimates BMR with the Mifflin-St Jeor formula, then multiplies by an activity factor.
Are calorie calculators exact?
No. They are estimates. Track real-world weight and energy changes to adjust over time.
Should I use this for medical nutrition advice?
No. Talk with a qualified professional for medical, eating disorder, pregnancy, or disease-specific nutrition guidance.
Which calorie formula does this use?
The calculator uses a standard equation-based estimate for maintenance calories. Real needs can differ, so weight trends and professional guidance matter.
When should I ask a clinician?
Ask a clinician or qualified nutrition professional when pregnancy, medication, medical history, eating disorder risk, symptoms, or disease-specific guidance matters.
Why can health formulas be misleading?
Health formulas simplify age, sex, body composition, training status, measurement method, pregnancy, and medical context into a planning estimate.
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