Answer: Enter your details and the Calorie Calculator returns your personalized daily target with the underlying calculation shown step by step.
A calorie calculator estimates how many calories you burn per day (your TDEE) from your age, sex, height, weight, and activity level, forming the basis for weight-loss or muscle-gain targets.
Calculate daily calorie needs (TDEE)
This calorie calculator estimates your daily calorie needs — your TDEE, or total daily energy expenditure — from your sex, age, height, weight, and activity level. It computes your BMR with the Mifflin-St Jeor equation, then applies an activity multiplier to return maintenance calories, plus targets for weight loss and gain.
Mifflin-St Jeor, published in 1990, is the predictive equation the Academy of Nutrition and Dietetics recommends for healthy adults, and it is more accurate for modern populations than the older Harris-Benedict formula. BMR — basal metabolic rate — is the energy your body burns at complete rest just to run organs, breathing, and temperature regulation; it is typically the largest single share of daily expenditure.
Mifflin-St Jeor for men is 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women it is 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161. TDEE = BMR × activity factor, using standard multipliers from 1.2 for sedentary up to 1.9 for very active training or physical jobs.
Worked example: a 30-year-old man at 75 kg and 178 cm has BMR = 750 + 1112.5 − 150 + 5 = 1,718 kcal; at moderate activity (1.55) his maintenance is about 2,660 kcal/day. A 30-year-old woman at 62 kg and 165 cm has BMR = 620 + 1031 − 150 − 161 = 1,340 kcal, or roughly 1,840–2,320 kcal at light-to-moderate activity.
The Dietary Guidelines for Americans publish estimated calorie needs by age and sex, spanning sedentary through active. They're a useful sanity check on any formula, and the spread inside each row shows how much activity alone moves the answer:
| Group | Estimated calories per day |
|---|---|
| Women, 19–30 | 1,800 – 2,400 |
| Women, 31–59 | 1,800 – 2,200 |
| Women, 60+ | 1,600 – 2,000 |
| Men, 19–30 | 2,400 – 3,000 |
| Men, 31–59 | 2,200 – 3,000 |
| Men, 60+ | 2,000 – 2,600 |
Two honest caveats apply to every number above. A formula is a starting estimate, and your own data settles it: hold intake steady for two or three weeks, watch the weekly weight average, and adjust by 100–200 calories from there. For the full walk-through, including how to pick your activity level honestly and where the floors are, see how many calories you should eat in a day.
The activity factors below are the widely used Harris-Benedict-derived multipliers. Be honest with yourself here — the difference between 'sedentary' and 'moderate' is 350+ calories a day, larger than most people's entire weight-loss deficit.
The example column shows maintenance calories for the 30-year-old, 75 kg, 178 cm man from the worked example above, so you can see how sensitively the estimate moves with activity.
| Activity level | Multiplier | Maintenance kcal (example man) |
|---|---|---|
| Sedentary (little/no exercise) | 1.2 | ~2,060 |
| Light (1–3 days/week) | 1.375 | ~2,360 |
| Moderate (3–5 days/week) | 1.55 | ~2,660 |
| Active (6–7 days/week) | 1.725 | ~2,960 |
| Very active (2x/day, physical job) | 1.9 | ~3,260 |
A pound of body fat stores roughly 3,500 kcal, so the classic guidance is a 500 kcal/day deficit for about one pound (0.45 kg) per week of loss, or a similar surplus for gain — though real bodies adapt and slow, and 0.5–1% of body weight per week is the more durable target. Very low calorie diets should not be attempted without medical supervision.
Treat the output as an estimate with a margin of a couple hundred calories, then let the scale calibrate it: track intake and weight for two or three weeks and adjust. Muscle gain works best with a modest surplus and resistance training; maintenance is simply eating to a stable weight. Energy needs also decline slightly with age as lean mass drops, so re-run the numbers periodically.
Where the calories go is roughly: BMR is the largest share for most people, followed by activity — both exercise and the mundane movement called NEAT (non-exercise activity thermogenesis), like walking and fidgeting — then the thermic effect of food, the energy cost of digesting meals, at roughly 10% of intake. Two people with identical stats can maintain on noticeably different intakes because NEAT varies widely between individuals.
Macronutrients set the composition of those calories: protein and carbohydrate supply about 4 kcal per gram, fat about 9, and alcohol 7. Protein deserves priority in almost every plan because preserving lean mass during a deficit — and building it during a surplus — depends on adequate protein intake paired with resistance training. Hydration, fiber, and micronutrients round out a diet that supports training rather than merely hitting a calorie number.
Track pragmatically. Weighing food for a couple of weeks calibrates your eye for portions; after that, estimating works well enough because TDEE itself is an estimate. Weekly averages beat daily weigh-ins for judging trends, since body water swings by a kilogram or more day to day with sodium and carbohydrate intake. Recalculate your needs after every 5 kg or so of weight change, because a smaller body burns less.
What is TDEE?
Total daily energy expenditure — the calories you burn in 24 hours including activity. It equals BMR × an activity factor from 1.2 (sedentary) to 1.9 (very active).
What is the Mifflin-St Jeor equation?
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 for men, minus 161 instead of plus 5 for women. Published in 1990, it is the recommended predictive equation for healthy adults.
How many calories should I eat to lose weight?
A common starting point is maintenance minus 500 kcal/day, which works out to roughly one pound (0.45 kg) per week, since a pound of fat stores about 3,500 kcal. A gentler 250–500 kcal deficit is easier to sustain.
How accurate is a calorie calculator?
Reasonably — Mifflin-St Jeor lands within about 10% for most healthy adults, but individual metabolism varies. Track weight for 2–3 weeks and adjust intake based on the trend.
Does calorie need change with age?
Yes — energy needs fall slightly with age, largely from declining lean mass, which is why the equation subtracts 5 kcal per year of age. Re-estimate after major weight or activity changes too.
Is 1,200 calories a day safe?
1,200 is the floor most health authorities cite for women, and 1,500 for men; below those, covering protein and micronutrients gets difficult without a doctor or dietitian involved. It's also unnecessarily low for most active people, who can lose weight steadily at 1,800–2,200.
Do I need to eat back the calories I burn exercising?
Usually no, if you picked the right activity level. The "moderate" option already assumes exercise 3–5 days a week, so logging workouts on top of it double-counts them. The exception is genuine one-off volume — a race day or a manual-labor shift — where a few hundred extra calories protect performance and recovery.