Calorie Calculator

Mifflin-St Jeor calorie formula

This calculator estimates basal metabolic rate, or BMR, with the Mifflin-St Jeor equation. For men, the formula is BMR = 10W + 6.25H − 5A + 5. For women, it is BMR = 10W + 6.25H − 5A − 161. W is weight in kilograms, H is height in centimeters, and A is age in years. If you choose imperial units, pounds are converted to kilograms and inches are converted to centimeters before the formula is applied.

BMR is the estimated energy your body uses at rest. To estimate total daily energy expenditure, or TDEE, the calculator multiplies BMR by an activity factor. Sedentary days use 1.2, light activity uses 1.375, moderate activity uses 1.55, very active uses 1.725, and extra active uses 1.9. This gives a practical maintenance estimate for planning meals or comparing goals.

Maintenance, loss and gain targets

The maintain result is the estimated calories per day to keep weight roughly stable at the selected activity level. The lose target subtracts 500 calories from maintenance, while the gain target adds 500 calories. Those are common planning shortcuts, not personalized medical prescriptions. Smaller adjustments may be more appropriate for some people, and large deficits can be unsafe or hard to sustain.

Accuracy and privacy notes

Calorie needs vary with body composition, training, sleep, hormones, medications and tracking accuracy. Treat this as a starting estimate, then compare it with real weight and energy trends over several weeks. The page does not upload age, sex, height, weight or goals. It simply runs the formula in your browser so you can explore scenarios privately and adjust with professional guidance if needed.

Worked example

Take a 30-year-old man who is 180 cm tall, weighs 80 kg and trains three to five days a week. His BMR is 10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 1,780 kcal. With the moderate factor of 1.55, TDEE is about 2,759 kcal, so the lose and gain targets are roughly 2,259 and 3,259 kcal per day.

Choosing the activity level honestly is the biggest lever. Most people overestimate it; if your job is desk-based and you exercise a few times a week, light or moderate is usually more realistic than very active. The formula was developed for adults, so it is not suited to children, pregnancy or medically supervised diets. After entering your numbers, eat near the target for two or three weeks, track your average weight, and adjust by 100–200 calories rather than making large jumps.