How this calculator works
- Step 1Your body70 kg, 170 cm, 30Weight, height, age and sex.
- Step 2Resting energy1,618 kcal/dayMifflin–St Jeor equation.
- Step 3× activity level1.55FAO/WHO/UNU physical activity level.
- Step 4Daily energy2,507 kcal/dayYour estimated TDEE.
BMR, or basal metabolic rate, is the energy your body uses at rest to keep breathing, circulating blood and holding its temperature. TDEE, total daily energy expenditure, adds everything you do in a day.
The calculator estimates resting energy with the equation Mifflin and colleagues published in 1990. It then multiplies by a physical activity level from the FAO, WHO and UN University report on human energy requirements.
Worked example: a man of 30, 70 kg and 170 cm
- Men
10 × kg + 6.25 × cm − 5 × age + 5- Women
10 × kg + 6.25 × cm − 5 × age − 161- TDEE
BMR × PAL
- Weight term10 × 70700
- Height term6.25 × 1701,062.5
- Age term− 5 × 30− 150
- Constant for men+ 5
- BMR1,618 kcal/day
- TDEE at PAL 1.552,507 kcal/day
A woman of the same age, 60 kg and 160 cm has a BMR of 1,289 kcal/day. The two equations differ only in their constant.
Activity changes the answer most
The FAO/WHO/UNU report groups lifestyles into three bands. Levels above 2.40 are hard to keep up for long, so the calculator stops at 2.20.
Weight and age
- At 80 kg1,718 kcal/dayTen more kilograms adds 100 kcal a day at rest.
- At age 501,518 kcal/dayTwenty more years takes away 100 kcal a day.
Reading the result and its limits
Treat the figure as a starting estimate: the equation predicts the average person of your size, and individuals differ.
The equation was built from measurements of 498 healthy adults aged 19 to 78, both normal weight and obese. It predicts resting energy, which is close to but slightly above strict basal energy.
It is not designed for children, pregnancy, illness or elite athletes. A doctor or dietitian can give advice that fits you.
From energy to meals
A daily energy estimate is the start of a meal plan. Macros and protein come next.
To split calories into protein, carbs and fat, use the macro calculator. The protein intake calculator follows ICMR-NIN 2020 guidance, and the BMI calculator shows your category.
Common mistakes
Mistake: Choosing a high activity level for one hard workout a week.
Instead: Pick the level that matches a typical week; if unsure, go lower.
Mistake: Reading the figure as exact.
Instead: Expect your real needs to differ by 10% or more.
Mistake: Eating below your BMR to lose weight faster.
Instead: Ask a doctor or dietitian before making large changes.
Methodology and sources
A separate script recomputes every figure from the paper’s sex-coded form in exact fractions and checks the unsimplified regression agrees within 1%.
The equations come from Mifflin et al., American Journal of Clinical Nutrition, 1990. The activity bands come from Table 5.3 of Human Energy Requirements, FAO/WHO/UNU, 2004. Sources, the review date and the health disclaimer follow.
Read how we test our calculators, or browse more health calculators.