Calorie Calculator
Estimate your BMR, maintenance calories (TDEE), and a daily calorie target for your goal
"How many calories should I eat" really has two parts: how much your body burns at rest, and how much more it burns from daily activity and exercise. This calculator estimates both separately using a published equation, then shows a daily target for maintaining, losing, or gaining weight, with the underlying assumptions listed out so nothing is a black box.
- BMR from the Mifflin-St Jeor equation: 10 × kg + 6.25 × cm − 5 × age − 161.
- Activity multiplier of 1.375 applied to BMR to estimate TDEE.
- No deficit or surplus applied.
- Macros use 4 kcal per gram of carbs and protein and 9 kcal per gram of fat.
Maintenance Calories by Activity Level
Based on your BMR of 1,375 kcal from the inputs above.
| Activity Level | Maintenance Calories |
|---|---|
| Sedentary (little or no exercise) | 1,650 kcal |
| Lightly active (exercise 1 to 3 days a week) ← Current | 1,891 kcal |
| Moderately active (exercise 3 to 5 days a week) | 2,132 kcal |
| Very active (hard exercise 6 to 7 days a week) | 2,372 kcal |
| Extra active (hard exercise plus a physical job) | 2,613 kcal |
BMR vs TDEE
BMR (basal metabolic rate) estimates the calories your body uses at complete rest. TDEE (total daily energy expenditure) multiplies BMR by an activity factor to estimate what you burn in a normal day, including movement and exercise. Your TDEE is your estimated maintenance calories: the intake at which your weight would stay roughly the same.
Calorie Deficit and Calorie Surplus
Eating below maintenance is a calorie deficit, and eating above it is a calorie surplus. A common rule of thumb says about 3,500 kcal equals one pound of body weight, so a 500 kcal daily deficit is often described as about one pound a week. It is only an approximation, because your body adapts as your weight and activity change.
Metric vs Imperial Inputs
The equation works in kilograms and centimeters. If you choose imperial units, pounds and feet and inches are converted for you before the calculation, so both give the same answer.
Worked Examples
A 35-year-old woman at 165 cm and 68 kg has a BMR of about 1,375 kcal. At a lightly active multiplier of 1.375, her TDEE, or maintenance level, comes to about 1,891 kcal a day.
A 30-year-old man at 180 cm and 85 kg has a BMR of about 1,830 kcal, and at moderate activity a TDEE of about 2,837 kcal. A 500 kcal daily deficit brings his target to about 2,337 kcal, which works out to roughly 1 lb (0.45 kg) of weight loss a week on paper.
A 25-year-old woman at 160 cm and 55 kg has a BMR of about 1,264 kcal, and at a sedentary multiplier a TDEE of about 1,517 kcal. Adding a gentle 250 kcal surplus brings her target to about 1,767 kcal, roughly half a pound of gain a week on paper.
Equation: Mifflin MD, St Jeor ST, et al. Am J Clin Nutr. 1990;51(2):241-247. Activity multipliers are common estimates, not exact values. This tool is for general information only.