Calorie Calculator Guide: TDEE, BMR & Weight Loss
To lose, gain, or maintain weight, you need to know how many calories your body actually burns in a day. That number — your TDEE (Total Daily Energy Expenditure) — is built from your resting metabolism plus an activity multiplier. This guide explains each piece and how to use them to reach your goal.
BMR — Your Basal Metabolic Rate
BMR is the energy your body burns at complete rest, just to keep you alive. The most accurate formula for most people is the Mifflin-St Jeor equation:
- s = +5 for men, −161 for women
This gives calories/day at rest, before any activity.
Example: a 30-year-old woman, 65 kg, 165 cm: BMR = 10(65) + 6.25(165) − 5(30) − 161 = 650 + 1031 − 150 − 161 ≈ 1,370 kcal/day.
TDEE — Adding Activity
Multiply BMR by an activity factor to get total daily burn:
| Activity Level | Multiplier |
|---|---|
| Sedentary (desk job, no exercise) | × 1.2 |
| Light (1–3 days/week) | × 1.375 |
| Moderate (3–5 days/week) | × 1.55 |
| Very active (6–7 days/week) | × 1.725 |
Our example woman at "light" activity burns 1,370 × 1.375 ≈ 1,884 kcal/day.
Building a Weight-Loss Deficit
A pound of body fat ≈ 3,500 kcal. To lose 1 lb/week, eat 500 kcal/day below TDEE. For the example, that's ~1,384 kcal/day.
Eating below ~1,200 kcal/day (women) or ~1,500 (men) for long periods can slow metabolism and cause nutrient deficiencies. Aim for a 300–500 deficit and adjust based on results.
Calories vs. Macros
Calories determine weight change; macros (protein/carbs/fat) determine composition. For weight loss with muscle retention, aim for ~0.7–1 g of protein per pound of body weight.
Put It Into Practice
Enter your stats and activity level to see your BMR, TDEE, and a calorie target for losing, maintaining, or gaining weight.