Reckonary / Health / Calorie (BMR) calculator
Daily calories to maintain
This calculator estimates how many calories your body burns in a day, so you can see roughly how much to eat to stay at your current weight. It starts from your resting metabolism and then accounts for how active you are.
Your basal metabolic rate (BMR) is the energy your body uses at complete rest — keeping your heart beating, your lungs working, and your temperature steady. We calculate it with the Mifflin-St Jeor equation, which uses your weight, height, age, and sex. Your total daily energy expenditure (TDEE) is that BMR multiplied by an activity factor, and it is the number you would aim to match to hold your weight steady.
Movement adds up. A desk-bound day burns far fewer calories than one spent on your feet or training hard. The activity slider applies a standard multiplier: from sedentary at 1.2 up to very active at 1.9. Pick the level that honestly matches a typical week. To lose weight, eat below this figure; to gain, eat above it.
These formulas give a solid estimate, but real bodies vary. Two people of the same size can burn noticeably different amounts. Use the result as a baseline, watch how your weight responds over a few weeks, and adjust.
Is BMR the same as the calories I should eat?
No. BMR is what your body burns at complete rest. To maintain weight you eat closer to your TDEE, which is your BMR scaled up by how active you are.
Why do I get a different number than another calculator?
Calculators use different formulas. Some use the older Harris-Benedict equation, which tends to read a little higher than the Mifflin-St Jeor equation used here.
Should I eat back the calories I burn from exercise?
If you picked an activity level that already includes your workouts, those calories are baked in, so eating them back again would double-count. Only add them separately if you chose a sedentary level.
How often should I recalculate?
Recheck after your weight changes by several pounds or your routine shifts, since both your size and activity feed into the result.
Last reviewed June 2026. Calories are estimated with the Mifflin-St Jeor equation. For general guidance, not medical advice.