Calorie Calculator
Calorie Calculator — find your BMR and daily calorie needs. Get targets for weight loss, maintenance, or weight gain. Free, no signup.
About Calorie Calculator
The Calorie Calculator works out how many calories your body needs each day based on your age, sex, height, weight, and how active you are. The result includes your Basal Metabolic Rate (BMR) — the calories you burn at rest — your maintenance number (TDEE), and a table of daily calorie targets for every common goal, from weight loss to weight gain.
How it works
The calculator uses the Mifflin-St Jeor equation, the most widely validated BMR formula for general-population use:
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
TDEE is then BMR multiplied by an activity factor (1.2 for sedentary up to 1.9 for extra active). TDEE is your maintenance intake — the calorie level at which your weight stays stable.
Reading the results
The result table shows six calorie targets. Maintain weight (equal to your TDEE) is the anchor. Every row above it removes calories to create a deficit; every row below adds calories to create a surplus.
| Goal | Daily change | Expected weekly result |
|---|---|---|
| Extreme weight loss | −1,000 cal | ≈ −0.9 kg / −2 lb |
| Moderate weight loss | −500 cal | ≈ −0.45 kg / −1 lb |
| Mild weight loss | −250 cal | ≈ −0.23 kg / −½ lb |
| Maintain weight | 0 | — |
| Mild weight gain | +250 cal | ≈ +0.23 kg / +½ lb |
| Moderate weight gain | +500 cal | ≈ +0.45 kg / +1 lb |
The rate-of-change figures assume the deficit or surplus comes predominantly from fat (or muscle, on a surplus with training). Real results depend on food composition, training, sleep, and individual metabolism.
Accuracy and limitations
The Mifflin-St Jeor formula is accurate to within 10–15% for most non-athletic adults. It’s a population average, so individuals at the extremes — very high muscle mass, very low muscle mass, thyroid conditions — will see more deviation. Use the output as a starting estimate, then track your actual weight over 2–3 weeks. If you’re losing faster than expected, add 100–200 cal; slower, subtract the same.
For anyone with medical conditions affecting metabolism (hypothyroidism, diabetes, history of eating disorders), verify targets with a registered dietitian before acting on them.
All calculations happen in your browser. No data leaves your device. Free, no signup, no watermark.
Frequently asked questions
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs running. It's the floor below which you should never eat long-term. TDEE builds on top of it by factoring in how much you move.
TDEE (Total Daily Energy Expenditure) is your maintenance calorie number — the amount you burn in a day including all activity. Eat at TDEE and your weight stays stable. Eat less to lose weight, eat more to gain.
The Mifflin-St Jeor equation, which is the most widely validated formula for estimating BMR in non-athletic adults. BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 (men) or − 161 (women). TDEE = BMR × activity multiplier.
Within 10–15% for most people. The formula is population-averaged, so it works well for typical body compositions. Athletes with unusually high muscle mass will see higher real-world calorie needs than the formula predicts; people with very low muscle mass may see lower needs. Treat the output as a starting estimate — track real intake vs. weight change over 2–3 weeks to calibrate.