Calorie / TDEE Calculator
Estimate your daily calorie needs with the Mifflin-St Jeor equation — BMR, maintenance calories (TDEE), and targets for weight loss or gain, with the formula and assumptions stated. Informational only, not medical advice.
| Goal | Calories / day |
|---|---|
| Lose ~1 lb / week | 1,770 kcal |
| Lose ~0.5 lb / week | 2,020 kcal |
| Maintain weight | 2,270 kcal |
| Gain ~0.5 lb / week | 2,520 kcal |
| Gain ~1 lb / week | 2,770 kcal |
How to use this tool
- Enter your age, sex, height, and weight (US or metric).
- Pick the activity level that best matches a typical week.
- Read your BMR, your TDEE (maintenance calories), and the goal table for losing or gaining weight.
How it works
BMR (basal metabolic rate) uses the Mifflin-St Jeor equation: 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 for males, or −161 for females. It's the energy your body burns at complete rest, and research has found it the most reliable of the common formulas for the general population.
TDEE multiplies BMR by an activity factor (1.2 sedentary up to 1.9 very active). The goal table applies the common rule of thumb that ~500 kcal/day below maintenance approximates a pound of weight loss per week — a simplification, since metabolism adapts over time.
These are population-level estimates that can miss an individual by several hundred calories. Use them as a starting point, adjust based on real-world results over a few weeks, and involve a doctor or registered dietitian for significant weight changes or any medical condition. This is not medical advice.
Sources & references
- Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure (Am J Clin Nutr, 1990)
- Frankenfield D, et al. Comparison of predictive equations for resting metabolic rate (J Am Diet Assoc, 2005)
Content last reviewed: July 2026.
Frequently asked questions
How many calories should I eat a day?
It depends on your size, age, sex, and activity — that's exactly what TDEE estimates. Eat near your TDEE to maintain weight, below it to lose, above it to gain. Individual needs vary, so treat the number as a starting point to adjust from.
What's the difference between BMR and TDEE?
BMR is what your body burns at complete rest; TDEE adds everyday movement and exercise on top. You should compare your food intake to TDEE, not BMR.
Why does the calculator ask for sex?
The Mifflin-St Jeor equation has different constants for males and females because of average body-composition differences. If neither fits you well, the two results bracket the likely range.
Is a 500-calorie deficit safe?
It's the conventional moderate approach (~1 lb/week), but the right deficit depends on your starting point and health. Very low intakes shouldn't be attempted without medical supervision.