Estimate resting energy expenditure from age, height, weight and the selected formula. The calculator also models daily energy use with an activity multiplier. These are estimates from your inputs, rather than measurements of your metabolism or a personal eating plan.
Scope: Use the explanation below for adult educational comparisons. The calculator clears its results for ages under 18 and for the pregnancy, breastfeeding or medical-condition options. People in these groups, or with other nutritional concerns, need individual guidance.
BMR Calculator
Estimate adult resting energy with multiple formulas and compare daily maintenance calories, goal calories, macros, BMI, meal splits and calorie-gap assumptions.
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Your BMR Result
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Enter your details to estimate BMR, TDEE, calories, and macros.
Calories Chart
Macro Breakdown Chart
Detailed BMR Breakdown
| Item | Estimated Value | Explanation |
|---|---|---|
| Click calculate to generate your BMR breakdown. | ||
Macro and Meal Plan
| Macro | Daily Target | Per Meal | Calories |
|---|---|---|---|
| Macro plan will appear after calculation. | |||
Smart Calorie Tips
Understand the BMR estimate
The name BMR refers to basal metabolic rate. The commonly used Mifflin–St Jeor equation on this page predicts resting energy expenditure. A formula result is not the same as a metabolic measurement made under controlled conditions. In the original study, resting expenditure was measured with indirect calorimetry and then used to develop the prediction equation. Mifflin and colleagues’ original study.
How to use the calculator
- Choose metric or US units and enter age, weight and height. Check the units after changing the selector.
- Select the equation you want to compare. Use Mifflin–St Jeor or revised Harris–Benedict if you do not have a body-fat estimate. A body-fat-based calculation needs that additional input.
- Choose an activity setting to explore a daily-energy scenario. Leave extra exercise calories at zero if that activity is already represented by your selected setting.
- Read the resting-energy result separately from maintenance, goal calories and macros. Changing a goal or meal setting does not turn the calculation into a clinical recommendation.
Mifflin–St Jeor formula and example
Use weight W in kilograms, height H in centimetres and age A in years. The simplified equations return kilocalories per day:
- Male equation:
10 × W + 6.25 × H − 5 × A + 5 - Female equation:
10 × W + 6.25 × H − 5 × A − 161
For the calculator’s example of 81 kg, 168 cm, age 27 and the male equation:
810 + 1,050 − 135 + 5 = 1,730 kcal/day.
The original equation was developed from 498 healthy adults aged 19–78. That study population does not establish accuracy for every individual or medical situation. Equation and study population.
What the other formula choices mean
- Revised Harris–Benedict: an alternative equation using the same weight, height, age and sex inputs with different coefficients. A difference between its answer and Mifflin–St Jeor is a difference between models, not proof that either measured your metabolism. Roza and Shizgal’s reevaluation.
- Katch–McArdle option: this calculator estimates lean mass as
weight × (1 − body fat % ÷ 100), then applies370 + 21.6 × lean mass in kg. An uncertain body-fat input carries through to the result. Do not select this option with an empty body-fat field and assume a body-fat-based estimate was made. - Average available formulas: the tool averages the formula results it can calculate. Averaging models is not a validation method or a guarantee of greater accuracy.
Resting calories and daily energy use are different
In this calculator, the maintenance estimate is calculated as resting estimate × activity multiplier + extra exercise calories. The activity choices use multipliers from 1.2 to 1.9. They are assumptions you choose; the website does not measure your movement or exercise.
Using the 1,730 kcal example and the moderate setting of 1.55, with no extra exercise entered, gives 1,730 × 1.55 = 2,681.5, displayed as about 2,682 kcal/day. This is an example of the model’s arithmetic, not an intake recommendation.
Adding the same exercise through both the activity choice and the extra-exercise field can count it twice. Changing a preset to obtain a preferred number does not make that number a measured energy requirement.
Limits of goals, macros and weekly projections
The goal and macro panels convert selected settings into calorie and nutrient amounts. They do not assess medical history, nutritional adequacy, treatment needs or whether a goal is suitable. The calculator does not display a weekly weight-change prediction.
For a personal weight-management plan, discuss the estimate with a qualified clinician or registered dietitian. The US National Institute of Diabetes and Digestive and Kidney Diseases also restricts its own Body Weight Planner to adults and excludes pregnancy and breastfeeding from its intended use. NIDDK planner scope and limitations.
Questions about the result
Why do two calculators give different numbers?
Compare their formula, units, activity multiplier, body-fat input and extra-calorie assumptions. Even matching inputs cannot turn a prediction into an individual measurement.
Should I eat exactly the BMR number?
The resting estimate does not represent all of your daily energy use. It should not be used by itself to set an eating target.
Does the sex setting diagnose or describe my body composition?
No. It chooses one of the equation’s coefficients. The calculator does not measure hormones or body composition, and it does not establish which equation is appropriate for every person.
Why is the displayed result rounded?
The calculator displays whole kilocalories for its main energy outputs. Decimal precision in the arithmetic does not imply the same precision in predicting a person’s needs.