HEALTH
BMR calculator
Estimate an adult basal metabolic rate from body weight, height, age and the selected published Mifflin–St Jeor equation constant.
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No regional currency, unit or language profile is applied. This choice does not convert values or change formulas, results, routes or legal guidance.
Enter adult weight, height and age, then select the applicable published equation constant.
Estimated basal metabolic rate
1,623.75 kcal/dayThis is the estimated energy used at rest under the equation's assumptions.
This adult screening estimate is not a measurement, diagnosis, treatment plan or nutrition prescription. It is not designed for children, pregnancy, critical illness or individual clinical decisions.
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Verification and calculation details
- Purpose
- BMR calculator
- Variables and units
- Use the labelled fields and units shown in the calculator. Results use those units unless a conversion is stated.
- Formula and method
- The exact formula and worked example are shown below. Deterministic formula executed locally in the browser.
- Assumptions
- Only entered values and stated assumptions are included. Local fees, rules and professional requirements are excluded unless explicitly shown.
- Engine version
- 1.0.0
- Production verification baseline
- Release 63 · source
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How this calculator works
Mifflin–St Jeor adult estimate: BMR = 10 × weight in kilograms + 6.25 × height in centimetres − 5 × age in years + s, where s is +5 for the male equation or −161 for the female equation.
Variables and inputs
- Weight
- Required numeric input. 20 to 350 kilograms; decimal values supported.
- Height
- Required numeric input. 80 to 250 centimetres; decimal values supported.
- Adult age
- Required numeric input. whole years from 18 to 120.
- Published equation
- Required numeric input. male constant +5 or female constant −161.
How to interpret the result
The calculator returns estimated basal metabolic rate in kilocalories per day, selected published equation constant, plain-language interpretation of the resting-energy estimate. Read each output against the assumptions you entered, compare alternatives one variable at a time, and use the result as an estimate rather than a promise.
Common mistakes to avoid
- Mixing units or entering a rate as a decimal when the field requests a percentage.
- Rounding intermediate values instead of the final displayed result.
- Leaving out a cost, timing rule or local requirement listed in the assumptions below.
Practical uses
Use the bmr calculator to check a real scenario, compare a changed assumption and explain the arithmetic before relying on a quote, specification or decision.
Worked example
For a 35-year-old using the male equation at 70 kg and 175 cm, BMR = 10 × 70 + 6.25 × 175 − 5 × 35 + 5 = 1,623.75 kcal/day.
Assumptions and limitations
- weight is entered in kilograms and height is entered in centimetres
- age is entered as completed whole adult years
- the selected constant matches the published equation the user intends to apply
- the estimate describes resting energy expenditure rather than total daily calorie needs
- this predictive adult screening estimate is not indirect calorimetry or an individual measurement
- the source equation was developed for generally healthy adults and individual error can be material
- the calculator is not designed for children, pregnancy, critical illness or individual clinical decisions
- the result is not a diagnosis, treatment plan, nutrition prescription or guaranteed calorie requirement
Important notes
Results are estimates based on the values entered. Confirm rates, prices, units and professional requirements that apply in your location. Review the Answer Atlas Calculation Standard and corrections policy for formula, privacy and correction rules.
Frequently asked questions
What does a BMR estimate represent?
It estimates the energy an adult body may use at rest over one day. It does not include an activity multiplier and is not the same as total daily energy expenditure.
Why does the calculator ask me to select an equation?
The published Mifflin–St Jeor equations use different constants: +5 for the male equation and −161 for the female equation. The calculator does not infer this choice.
Is this BMR result a medical or nutrition recommendation?
No. It is a population-based adult estimate, not a measurement, diagnosis or individual calorie prescription. Qualified clinical advice may be needed for health decisions.