Resting Energy Estimate with Mifflin–St Jeor
The screen calls the result BMR, but the Mifflin calculation is an estimate of resting energy rather than a measured basal metabolic rate. It uses age, body measurements and a sex-specific equation constant.
- Runs in your browser
- Nothing is uploaded
- No signup; device limits apply
Numbers stay on your device. Nothing is sent to a server.
Mifflin–St Jeor was fitted on binary sex. It is a population equation, not an identity document.
Accepted after conversion: 30–300 kg (about 66–661 lb).
Accepted after conversion: 120–230 cm (about 47–91 in).
How to use this tool
Select metric or US units and enter adult measurements. The equation uses a +5 male constant or −161 female constant; this worksheet does not add energy for daily activity.
Results and examples
The output shows estimated kcal per day and the same energy multiplied by 4.184 for kJ. It should not be treated as a laboratory measurement or used directly as a daily food-intake prescription.
Worked example
For a 30-year-old male at 70 kg and 170 cm, the equation returns 1,617.5 kcal per day.
Limitations
- Pregnancy, breastfeeding, growth and disease-specific requirements are not modelled.
- The original study population and individual prediction error still need primary-paper review.
Fields
| Field | Guidance and constraints |
|---|---|
| Sex used by the equation | Mifflin–St Jeor was fitted on binary sex. It is a population equation, not an identity document. · Male coefficients / Female coefficients |
| Age (years) | Accepted range: 19–78 · Input step: 1 |
| Units | kg and cm / lb and inches |
| Weight | Accepted after conversion: 30–300 kg (about 66–661 lb). · Accepted range: 30–300 · Input step: 0.1 |
| Height | Accepted after conversion: 120–230 cm (about 47–91 in). · Accepted range: 120–230 · Input step: 0.1 |
Data handling
Processing stays in the current browser tab; the site does not upload tool input for the calculation itself.
Frequently asked questions
Is this a food-intake target?
No. It excludes activity energy and is not a dietary prescription.
Is the kJ figure a separate estimate?
No. It is a unit conversion of the same energy.
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