Mifflin-St Jeor estimate
Sample input
Formula: Mifflin-St Jeor Age: 30 Gender: Male Height: 180 cm Weight: 80 kg
Sample result
- BMR: 1,780 calories/day
- Sedentary estimate: 2,136 calories/day
- Moderate exercise estimate: 2,608 calories/day
BMR Calculator
Estimate your Basal Metabolic Rate and daily calorie needs using metric or imperial units.
Health & Fitnessavailable
BMR Calculator
Estimate basal metabolic rate and daily calorie needs from age, gender, height, weight, and activity level multipliers.
Units
Gender
Options
Formula
Result
Enter age, height, and weight to calculate BMR.
Estimate note
BMR and daily calorie needs are estimates only. Activity, body composition, health conditions, pregnancy, medication, and individual variation can affect real calorie needs. This tool is not medical advice.
About BMR Calculator
Use the BMR Calculator to estimate Basal Metabolic Rate from age, gender, height, and weight. Choose metric or imperial units, compare common BMR formulas, and see estimated daily calorie needs across activity levels.
How to use
- Choose Metric or Imperial units.
- Enter age, gender, height, and weight.
- Choose a formula in the options section. Mifflin-St Jeor is selected by default.
- Enter body fat percentage only when using Katch-McArdle.
- Review the live BMR estimate and daily calorie needs table, then copy the result if needed.
Worked example
Features
- Estimates BMR with metric or imperial units.
- Supports Mifflin-St Jeor, Revised Harris-Benedict, and Katch-McArdle formulas.
- Shows body fat percentage only when Katch-McArdle is selected.
- Converts imperial height and weight to metric before calculation.
- Shows estimated daily calorie needs across six activity levels.
- Formats BMR and calorie outputs as whole calories.
- Shows friendly messages for missing, invalid, or zero input values.
- Runs in the browser without requiring an account.
How it works
- All formulas use metric values internally, so imperial pounds and inches are converted before calculation.
- Mifflin-St Jeor uses weight, height, age, and gender to estimate BMR.
- Revised Harris-Benedict also uses weight, height, age, and gender with a different set of coefficients.
- Katch-McArdle estimates lean body mass from weight and body fat percentage, then calculates BMR from lean mass.
- Daily calorie needs are estimated by multiplying BMR by activity multipliers from sedentary through extra active.
- BMR and calorie estimates are rounded to whole calories for readability.
Common use cases
- Estimating baseline calorie needs from height, weight, age, and gender.
- Comparing Mifflin-St Jeor and Revised Harris-Benedict estimates.
- Using body fat percentage with Katch-McArdle when lean mass is relevant.
- Checking estimated maintenance calories for different activity levels.
- Recording BMR and TDEE estimates for personal tracking notes.
- Quickly converting imperial measurements into a metric-based BMR formula.
Frequently asked questions
What is BMR?
BMR, or Basal Metabolic Rate, is an estimate of the calories your body uses at rest for basic functions.
What is the difference between BMR and TDEE?
BMR estimates resting calorie needs. TDEE estimates daily calorie needs after applying an activity multiplier.
Which formula should I use?
Mifflin-St Jeor is the default because it is commonly used for modern BMR estimates. Revised Harris-Benedict is another standard option, and Katch-McArdle can be useful when you have a body fat estimate.
When does Katch-McArdle require body fat percentage?
Katch-McArdle uses lean body mass, so the calculator requires body fat percentage only when that formula is selected.
Can I use imperial units?
Yes. Enter height in feet and inches and weight in pounds. The calculator converts those values to metric before applying the formula.
What activity levels are included?
The tool includes sedentary, light exercise, moderate exercise, active, very active, and extra active multipliers.
Are BMR and calorie needs exact?
No. They are estimates. Activity, body composition, health conditions, pregnancy, medication, and individual variation can all affect real calorie needs.
Can age values outside 15 to 80 be used?
The calculator accepts positive ages and does not hard-crash outside typical adult ranges, but estimates may be less useful outside common adult use cases.
Does this calculator give medical advice?
No. It provides general estimates only and should not replace guidance from a qualified health professional.
Is my input stored by ToolMetro?
No. The BMR Calculator runs in your browser and does not require server-side processing or an account.