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BMR Calculator

Use this BMR Calculator to estimate adult basal metabolic rate from weight, height, and age. The page shows both common Mifflin-St Jeor equation constants so the difference between male and female estimates is clear.

bmrbasal metabolic rateresting energymifflin st jeormetabolismcalories

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Calculator Inputs

Choose what you want to calculate, enter realistic values, adjust units where shown, and use the scenario section for repeated-use planning.

Input and Formula Breakdown

BMR is an estimate of resting energy use. This calculator applies the adult Mifflin-St Jeor structure with weight in kilograms, height in centimeters, age in years, and a sex-specific constant. Use the result as a starting estimate, not a diagnosis or calorie prescription.

Weight
72 lb(32.66 kg)
Height
175 in(444.5 cm)
Age
30 years
Estimated BMR - male equation
2,960 cal/day
Estimated BMR - female equation
2,794 cal/day
Equation constant difference
166 cal/day

Scenario and Comparison

Current

2,960 cal/day

Projected

35,516.54

Adjusted

3,255.68

Visual Comparison

Current result2,959.71
Projected usage35,516.54
Comparison scenario3,255.68

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Trust note

Important estimate

This BMR estimate is educational and is not medical or nutrition advice. Personal calorie needs should be reviewed with a qualified professional when health, weight, pregnancy, medication, training, or eating-disorder concerns are involved.

High risk contextDifficulty: easyConfidence estimate: 88/100Reviewed 2026-07-26Reviewed by: AZCalculate health calculator reviewCalculator vuces-2.1 / Formula vformula-1.02 sources listed

Formula and Explanation

BMR = 10W + 6.25H - 5A + S, where S is +5 for male and -161 for female

BMR is an estimate of resting energy use. This calculator applies the adult Mifflin-St Jeor structure with weight in kilograms, height in centimeters, age in years, and a sex-specific constant. Use the result as a starting estimate, not a diagnosis or calorie prescription.

Variable descriptions

W(kg)
Weight: Body weight used by the equation.
H(cm)
Height: Body height used by the equation.
A(years)
Age: Age in completed years.
S(kcal/day)
Sex constant: +5 for the male equation and -161 for the female equation.

Formula Notes

  • The male result uses 10W + 6.25H - 5A + 5.
  • The female result uses 10W + 6.25H - 5A - 161.
  • The equation is an adult population estimate and does not measure metabolism directly.
  • Daily calorie needs require activity, health context, and professional judgment beyond BMR.

Common uses

  • Estimate adult resting energy
  • Compare male and female BMR equation constants
  • Plan a starting point for daily calories
  • Understand metabolism estimates

Assumptions

What this calculation assumes

  • The user is an adult using kilogram, centimeter, and year inputs.
  • The calculator presents equation estimates rather than measured metabolism.
  • Activity level, body composition, medication, pregnancy, illness, and clinical nutrition needs are outside the formula.

Avoid mistakes

Quick checks before you rely on the result

  • Treating BMR as total daily calorie needs.
  • Using the adult equation for children or teenagers.
  • Assuming a formula can measure individual metabolism exactly.
  • Ignoring professional advice when medical conditions or nutrition risks are present.

Step-by-Step Explanation

Follow the reasoning, not only the final number.

  1. 1

    Set up the calculation

    Enter adult weight in kilograms, height in centimeters, and age in years.

    Starting with clearly defined values and units prevents the most common calculation errors.

  2. 2

    Work through step 2

    Calculate the shared base: 10 x weight + 6.25 x height - 5 x age.

    This step transforms the known values into the form required by the formula.

  3. 3

    Work through step 3

    Add +5 for the male equation or subtract 161 for the female equation.

    This step transforms the known values into the form required by the formula.

  4. 4

    Interpret the result

    Compare the two BMR estimates and use the relevant one as a starting point for broader calorie planning.

    Compare the result with your real-world goal, such as estimate adult resting energy.

Worked example

Adult BMR comparison example

Known values

  • Weight: 72 kg
  • Height: 175 cm
  • Age: 30 years

Calculation

  1. 1. Shared base = 10 x 72 + 6.25 x 175 - 5 x 30 = 1,663.75.
  2. 2. Male equation adds 5.
  3. 3. Female equation subtracts 161.

Result and meaning

Estimated BMR is about 1,669 cal/day with the male equation and 1,503 cal/day with the female equation.

Calculator guide

About this BMR Calculator

Estimate adult basal metabolic rate for male and female Mifflin-St Jeor equations using weight, height, and age.

References

Sources used for this calculator

Found something that does not look right?

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Calculator usage

Usage information loads after the calculator is ready.

FAQ

BMR Calculator FAQs

What does BMR mean?+

BMR means basal metabolic rate, an estimate of energy used at rest for essential body functions.

Which BMR equation does this calculator use?+

It uses the adult Mifflin-St Jeor structure with separate male and female constants.

Why are male and female BMR results different?+

The equation uses a different constant for each sex category, so the shared weight, height, and age base is adjusted differently.

Is BMR the same as daily calories?+

No. Daily calorie needs also depend on activity, goals, health context, and other factors.

Can I use this for children or teenagers?+

No. This page is intended for adult estimates. Children and teenagers need age- and sex-specific clinical growth context.

Is this medical advice?+

No. It is an educational estimate only and should not replace qualified health or nutrition advice.

Why might my real metabolism differ?+

Body composition, health conditions, medication, training, hormones, sleep, and measurement differences can all affect real energy needs.

What should I use after BMR?+

Use a calorie or TDEE-style planner to apply activity factors, then review the result with appropriate health context.

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