BMR Calculator
The calories your body needs at complete rest.
Last updated: January 2025 · Built for the 2024–25 financial year
Inputs
Results
BMR (per day)
1,718 kcal
Weekly baseline
12,023 kcal
Results are estimates only. For financial advice, consult a licensed adviser.
Overview
Basal Metabolic Rate — Mifflin-St Jeor (1990)
Your BMR is the number of calories your body burns at complete rest just to keep the lights on — heart, lungs, brain, kidneys, cellular repair. It accounts for 60-75% of total daily energy expenditure for most adults.
Mifflin-St Jeor is the formula recommended by the Academy of Nutrition and Dietetics for adults. It is more accurate for modern populations than the older Harris-Benedict equation.
Formula
Mifflin-St Jeor
Men: BMR = 10·kg + 6.25·cm − 5·age + 5 Women: BMR = 10·kg + 6.25·cm − 5·age − 161
Worked example
30-year-old man, 75 kg, 178 cm
- 10 × 75 = 750.
- 6.25 × 178 = 1,112.5.
- 5 × 30 = 150.
- BMR = 750 + 1,112.5 − 150 + 5 = 1,717.5 kcal/day.
Answer: ≈ 1,718 kcal/day at rest
Activity multipliers (BMR → TDEE)
| Lifestyle | Multiplier |
|---|---|
| Sedentary (desk job) | × 1.2 |
| Lightly active (1-3 days/wk) | × 1.375 |
| Moderately active (3-5 days/wk) | × 1.55 |
| Very active (6-7 days/wk) | × 1.725 |
| Athlete / physical job | × 1.9 |
Pro tips
- •BMR drops about 1-2% per decade after age 20.
- •Strength training builds lean mass — the only sustainable BMR lift.
- •Crash diets temporarily lower BMR (adaptive thermogenesis).