Calculator
BMR & TDEE calculator (Mifflin-St Jeor)
Your BMR is the energy your body needs at complete rest. Add activity and you get your TDEE – per day and per week.
In short
Mifflin-St Jeor equation: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5 for men, or − 161 for women. Multiply your BMR by an activity factor (1.2 to 1.9) to get your TDEE.
BMR (basal metabolic rate)
The energy your body uses at rest for breathing, circulation, organs and body temperature. For most people it's the largest part of daily energy use.
TDEE (total daily energy expenditure)
Your total daily burn: BMR plus energy for movement, exercise and digestion.
Worked example
A 32-year-old woman, 170 cm (5'7"), 75 kg (165 lb):
10 × 75 + 6.25 × 170 − 5 × 32 − 161 = 750 + 1,062.5 − 160 − 161 = 1,491.5 calories BMR. Lightly active (factor 1.375) that's about 2,051 calories per day or 14,357 calories per week.
Activity factors
| Activity | Factor |
|---|---|
| sedentary | 1.2 |
| lightly active | 1.375 |
| moderately active | 1.55 |
| very active | 1.725 |
| extremely active | 1.9 |
These factors are approximations. If Weekfuel counts your steps, choose a lower factor so movement isn't counted twice.
Why Mifflin-St Jeor?
In a systematic review of prediction equations, Mifflin-St Jeor most often predicted resting metabolic rate within ±10% of measured values in healthy adults (Frankenfield et al., 2005). Weekfuel uses the same equation.
Frequently asked questions
How accurate is a calculated BMR?
Formulas give estimates. For most people Mifflin-St Jeor lands within about 10% of a measured value; for individuals it can be more. Your weight trend shows whether the numbers work for you.
What's the difference between BMR and TDEE?
BMR covers rest only. TDEE adds movement, exercise and digestion.
Should I eat below my BMR?
To lose weight you eat below your TDEE, not necessarily below your BMR. Very low intake over longer periods should be medically supervised.