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Body Fat Calculator
Estimate body fat percentage with the US Navy tape-measure method, plus fat mass, lean mass and your ACE category.
Calorie Calculator
Estimate your daily calorie needs (BMR and TDEE) with the Mifflin-St Jeor equation, plus targets to lose or gain weight.
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How to use this calculator
Enter your values after choosing the type of calculation in the tabs. The result updates as you type; press Calculate to confirm and jump to the result on mobile. Use Share to send the calculator with your result.
Mifflin-St Jeor equation
Men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5
Women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161
TDEE = BMR × activity factor
Published by Mifflin, St Jeor et al. in 1990, it was found by the Academy of Nutrition and Dietetics’ evidence review to predict resting energy within 10% for more healthy adults than older equations such as Harris-Benedict. Example: a 30-year-old man, 80 kg and 180 cm: 800 + 1,125 − 150 + 5 = 1,780 kcal BMR; moderately active, about 2,760 kcal/day.
Activity factors
| Level | Factor |
|---|---|
| Sedentary (little or no exercise) | 1.2 |
| Light (exercise 1–3 days/week) | 1.375 |
| Moderate (exercise 3–5 days/week) | 1.55 |
| Very active (hard exercise 6–7 days/week) | 1.725 |
| Extra active (physical job + training) | 1.9 |
Calories and weight change
A deficit of about 500 kcal a day is the traditional estimate for losing roughly 1 lb (0.45 kg) a week. Real-world weight loss slows over time as your body adapts, so treat these as starting points and adjust every few weeks based on your actual trend.
Who shouldn’t rely on this
Pregnant or breastfeeding people, children, athletes with very high muscle mass and anyone with a medical condition affecting metabolism should get individual advice from a registered dietitian or doctor.
Frequently asked questions
How many calories should I eat a day?
Your maintenance level is your TDEE. To lose weight gradually, eat about 250–500 kcal below it.
What is the difference between BMR and TDEE?
BMR is energy used at complete rest; TDEE adds daily movement and exercise.
Is Mifflin-St Jeor accurate?
It’s one of the best-validated equations for healthy adults, usually within about 10%, but individuals vary.
About this tool
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- Expert review pending
- Last updated
- 31 Oct 2026
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