Calorie Needs Calculator

Estimate how many calories your body uses each day, plus gentle targets for losing or gaining weight.

How to use

1. Enter your age, sex, height, and weight.
2. Pick the activity level that best matches a typical week.
3. Click Calculate Calories to see your estimated BMR, maintenance level, and gentle loss and gain targets.

What the numbers mean

BMR (basal metabolic rate) is the energy your body uses at rest, estimated here with the Mifflin-St Jeor equation: for men, 10 x weight in kg + 6.25 x height in cm - 5 x age + 5; for women, the same formula with -161 instead of +5. Multiplying BMR by an activity factor gives maintenance calories — roughly what you use in a day. The loss target subtracts about 500 calories and the gain target adds about 500, which in theory shifts weight by roughly one pound per week, though real bodies vary.

Limits of the estimate

These are averages built from population data. Muscle mass, hormones, illness, medication, and how accurately you judge activity all move the true number, sometimes by several hundred calories. Activity multipliers are rough categories, not measurements. If your weight does not move as expected after several consistent weeks, the estimate — not your effort — is usually what needs adjusting, and a professional can help interpret the pattern.

Healthy next steps

Use maintenance as a starting point and change gradually. A modest deficit or surplus, regular meals, protein and fiber from ordinary foods, daily movement, and enough sleep are steadier than extreme cuts. Avoid very low intakes without professional guidance, and seek advice promptly if you have a health condition or a history of disordered eating.

Frequently Asked Questions

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