How to Calculate Your Daily Calorie Needs
Hesaplayıcı2 min read
Short answer
Your daily calorie need is your basal metabolic rate (BMR) times an activity factor. The Mifflin–St Jeor equation gives the BMR from weight, height, age and sex. For example, a moderately active woman of 31 years, 65 kg and 168 cm has a 1,384 kcal BMR and needs 2,145 kcal a day. This is general information, not medical advice.
Formula
BMR (men) = 10 × weight + 6.25 × height − 5 × age + 5
BMR (women) = 10 × weight + 6.25 × height − 5 × age − 161
daily calorie need = BMR × activity factor
- weight in kilograms, height in centimetres, age in years
- BMR: the basal metabolic rate, the energy your body uses in a day at rest (kcal per day). The equation is from Mifflin and colleagues, 1990.
- activity factor: the multiplier from the American Council on Exercise (ACE) table. Sedentary 1.2; lightly active (exercise 1–3 days a week) 1.375; moderately active (3–5 days) 1.55; very active (6–7 days) 1.725; extremely active (twice a day, physical job) 1.9.
The BMR and the daily need are rounded to whole kcal; the daily need uses the rounded BMR.
Step-by-step example
A woman of 31 years, 65 kg and 168 cm who exercises 3–5 days a week:
- BMR: 10 × 65 + 6.25 × 168 − 5 × 31 − 161 = 1,384 kcal.
- Activity factor: moderately active, 1.55.
- Daily calorie need: 1,384 × 1.55 = 2,145 kcal.
The same calculation for a sedentary man of 40 years, 80 kg and 180 cm: BMR 10 × 80 + 6.25 × 180 − 5 × 40 + 5 = 1,730 kcal, daily need 1,730 × 1.2 = 2,076 kcal.
How the activity level changes the result
The daily need of the same woman (BMR 1,384 kcal) by activity level:
| Activity level | Factor | Daily need |
|---|---|---|
| Sedentary | 1.2 | 1,661 kcal |
| Lightly active | 1.375 | 1,903 kcal |
| Moderately active | 1.55 | 2,145 kcal |
| Very active | 1.725 | 2,387 kcal |
| Extremely active | 1.9 | 2,630 kcal |
The BMR stays the same; only the factor changes the result. If you choose a higher level than you really have, your need looks higher than it is. Choose the level closest to your weekly exercise.
How to read the result
The result is the estimated energy to keep your weight; it is not a diet plan. The “calorie” on food labels is a kilocalorie (kcal). The equation comes from healthy adults; pregnancy, breastfeeding, illness, medicines and a high muscle share are not taken into account, and a measured value can differ from person to person. Ask your doctor or a dietitian about losing or gaining weight.
Worked example: A moderately active woman, 31 years, 65 kg, 168 cm
Daily calorie need
2,145 kcal/day
- Basal metabolic rate (BMR)
- 1,384 kcal/day
Step by step
Basal metabolic rate (BMR)
BMR = 10 × weight + 6.25 × height − 5 × age − 161
BMR = 10 × 65 + 6.25 × 168 − 5 × 31 − 161 = 1,384 kcal
Daily calorie need
daily energy need = BMR × activity factor
daily energy need = 1,384 × 1.55 = 2,145 kcal