How to calculate TDEE
Total daily energy expenditure (TDEE) is the energy you use in a day. Work out your resting energy with the Mifflin and St Jeor equation, then multiply by an activity factor. A 30 year old man of 80 kg and 180 cm moderately active comes to about 2,759 kcal.
Updated 21 October 2026. Sources named on the page.
- The two steps and the equation for women and men
- A worked example with every number shown
- How the activity factor changes the answer
- An estimate for adults, not a measurement
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Let the calculator do it
Enter your age, sex, height, weight and activity. It shows resting energy, the factor and the total in kcal and kJ.
Check your working
These known answers use the same equation as the calculator.
Known answers
| Person | Resting energy | Factor | TDEE |
|---|---|---|---|
| Man, 30 y, 80 kg, 180 cm | 1,780 kcal | 1.2 | 2,136 kcal |
| Man, 30 y, 80 kg, 180 cm | 1,780 kcal | 1.55 | 2,759 kcal |
| Woman, 30 y, 65 kg, 165 cm | 1,370 kcal | 1.2 | 1,644 kcal |
| Woman, 30 y, 65 kg, 165 cm | 1,370 kcal | 1.55 | 2,124 kcal |
Sources: Mifflin MD, St Jeor ST and others, American Journal of Clinical Nutrition, 1990; Activity factors are commonly used estimates, not measurements of any person
Figures and sources checked 21 October 2026. General information, not medical advice.
Step 1: resting energy
Resting energy (BMR) is what your body uses at rest. The Mifflin and St Jeor equation estimates it from weight in kilograms, height in centimetres and age in years.
- Men: 10 x weight + 6.25 x height - 5 x age + 5
- Women: 10 x weight + 6.25 x height - 5 x age - 161
Step 2: the activity factor
Multiply resting energy by a factor for how active you are: 1.2 for mostly sitting, 1.375 for light activity, 1.55 for moderate, 1.725 for very active and 1.9 for extremely active. The result is your TDEE, the energy that keeps your weight about steady.
Worked example for a man
Age 30, 80 kg, 180 cm. Resting energy: 10 x 80 = 800, plus 6.25 x 180 = 1,125, minus 5 x 30 = 150, plus 5, which is 1,780 kcal. Moderately active (x1.55): 1,780 x 1.55 = 2,759 kcal, or about 11,544 kJ.
Worked example for a woman
Age 30, 65 kg, 165 cm. Resting energy: 650, plus 1,031.25, minus 150, minus 161, which is 1,370 kcal. Mostly sitting (x1.2): 1,644 kcal. Light activity (x1.375): 1,884 kcal. Moderate (x1.55): 2,124 kcal.
Limits of the estimate
The equation is built from averages. Muscle, age, health, hormones and how much you really move can put your true figure a few hundred kcal either way. Use TDEE as a starting point and adjust from how you actually feel and what your weight does over weeks.
The figures are for adults aged 19 and over without a medical condition, not for pregnancy or breastfeeding.
Questions
Is TDEE the same as BMR?
No. BMR is the energy used at rest. TDEE adds the energy for daily movement and exercise, so it is higher.
How accurate is a TDEE calculator?
It is an estimate from averages. Real needs can differ by a few hundred kcal. Watch how your weight and energy behave over a few weeks and adjust.
Which activity level should I pick?
Pick the one that matches a typical week, and choose the lower one if you are unsure. The activity guide explains each level.
Does it work in kilojoules?
Yes. Multiply kcal by 4.184 for kJ. The calculator shows both.
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