Your result

What your result means

Using 77.1 kg, 175.3 cm and an age of 35 years, the Mifflin-St Jeor equation estimates a BMR of 1,696 kcal/day — about 70.7 kcal every hour even while asleep. The older revised Harris-Benedict equation gives 1,764 kcal/day, a difference of 67 kcal. Studies comparing the two generally find Mifflin-St Jeor closer to measured values in today’s adults, so we use it as the main result.

The math

Formula and sources

Formula

Mifflin-St Jeor (1990)
  men:   10W + 6.25H − 5A + 5
  women: 10W + 6.25H − 5A − 161
Revised Harris-Benedict (Roza & Shizgal, 1984)
  men:   88.362 + 13.397W + 4.799H − 5.677A
  women: 447.593 + 9.247W + 3.098H − 4.330A

W: weight (kg)
H: height (cm)
A: age (years)

Strictly, Mifflin-St Jeor predicts resting energy expenditure (REE), which is measured under slightly less strict conditions than true basal rate; the two are close and the terms are used interchangeably.

Sources we checked this against

1Mifflin MD et al., A new predictive equation for resting energy expenditure in healthy individuals (Am J Clin Nutr, 1990)PubMed / NIH National Library of Medicine · pubmed.ncbi.nlm.nih.gov
2BMR Calculator – how to calculate your BMR (worked example)Mt. San Antonio College Kinesiology · mtsac.edu
3Roza AM, Shizgal HM. The Harris Benedict equation reevaluated (Am J Clin Nutr, 1984)PubMed / NIH National Library of Medicine · pubmed.ncbi.nlm.nih.gov

Formula last checked 2026-11-04. Found an error? Tell us and we will fix it.

Step by step

Two worked examples

Example 1

MtSAC example

BMR (Mifflin-St Jeor)

1,787 kcal/day

Sex: Male
Age: 20 years
Units: US (ft, in, lb)
Height (feet): 5 ft
Height (inches): 10 in
Weight: 170 lb

MtSAC converts 170 lb ÷ 2.2 and 70 in ÷ 0.4 and gets about 1,772 kcal. With exact conversion (77.1 kg, 177.8 cm): 771 + 1,111 − 100 + 5 ≈ 1,787 kcal/day. Harris-Benedict gives 1,861 kcal/day.

Example 2

Same person at 50

BMR (Mifflin-St Jeor)

1,637 kcal/day

Sex: Male
Age: 50 years
Units: US (ft, in, lb)
Height (feet): 5 ft
Height (inches): 10 in
Weight: 170 lb

Thirty more years subtract 5 × 30 = 150 kcal in Mifflin-St Jeor, giving 1,637 kcal/day; Harris-Benedict drops to 1,691 kcal/day.

Comparison of the two examples
Result	Example 1	Example 2
BMR (Mifflin-St Jeor)	1,787 kcal/day	1,637 kcal/day
BMR (revised Harris-Benedict)	1,861 kcal/day	1,691 kcal/day

Questions

Frequently asked questions

What is the difference between BMR and TDEE?

BMR is energy at rest. Total daily energy expenditure adds digestion and every bit of movement, usually 20% to 90% more. Use the calorie calculator to estimate TDEE.

Why does BMR fall with age?

Mostly because people tend to lose muscle and gain fat with age, and muscle burns more energy at rest. Strength training helps preserve it.

Can I raise my BMR?

Building muscle raises it modestly. Larger changes in daily calorie burn come from activity rather than from BMR itself.

BMR Calculator

Your details

Two equations side by side