BMR Calculator — Basal Metabolic Rate
Calculate your Basal Metabolic Rate (BMR) with the Mifflin-St Jeor equation. See how many calories your body burns at rest.
Formula and sources updated · Data sources · 1View algorithm, constants and default inputs (JSON)
About this calculator
This calculator estimates resting energy expenditure with the Mifflin–St Jeor equation from weight, height, age and the equation’s male/female constant. It is intended for adults in the age range shown and is not a measurement or a daily calorie target; activity and individual variation are not included.
Worked example
calculated with the default values below
Weight 70 kg · Height 170 cm · Age 30 years · Sex Male BMR 1,618 kcal/day
Method and assumptions
Formula basis and scope
Uses the rounded Mifflin–St Jeor equation: 10W + 6.25H - 5A + 5 for the male option, or -161 for the female option; W in kg, H in cm and A in years.
A population prediction of adult resting energy needs, not a measured metabolic rate or an individual dietary prescription.
Data sources
Disclaimer
These calculators are for general information only and are not a medical device, a diagnosis or a treatment plan. Reference ranges describe populations, not individuals, and do not account for pregnancy, medication, disability or athletic training. Discuss your own situation with a qualified healthcare professional.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
BMR = 10w + 6.25h − 5a + c; c = 5 (♂) | −161 (♀)
- w
- Weight (kg)
- h
- Height (cm)
- a
- Age (years)
- c
- Sex constant (5 male, −161 female)
- BMR
- Basal metabolic rate (kcal/day)
Mifflin–St Jeor equation; height must be in centimetres and weight in kilograms.
Frequently asked questions
Should I eat exactly my basal metabolic rate?
This tool estimates basal metabolic rate using the Mifflin–St Jeor equation. BMR estimates energy use at rest; it does not include ordinary movement or exercise. Compare it with estimated total daily expenditure before planning food intake. An individual’s actual needs can differ from the formula.
Which prediction equation does this tool use?
It uses Mifflin–St Jeor: 10 × weight in kilograms + 6.25 × height in centimetres − 5 × age in years, then adds 5 for the male setting or subtracts 161 for the female setting. It does not offer Harris–Benedict or Katch–McArdle. The result is an estimate, not a direct measurement.