Calorie Calculator
Estimate how many calories you need per day to maintain, lose, or gain weight.
This tool provides general estimates for informational purposes only and is not a substitute for personalized medical or nutritional advice.
| Activity level | Male | Female |
|---|---|---|
| Sedentary | 2,039 cal | 1,839 cal |
| Light (1–3 days/wk) | 2,336 cal | 2,107 cal |
| Moderate (3–5 days/wk) | 2,633 cal | 2,376 cal |
| Active (6–7 days/wk) | 2,930 cal | 2,644 cal |
| Very active | 3,228 cal | 2,912 cal |
How your calorie estimate is calculated
The calculator works in two steps. First it estimates your basal metabolic rate (BMR), the energy your body uses at rest, with the Mifflin-St Jeor equation:
Men: BMR = 10 × weight in kg + 6.25 × height in cm minus 5 × age + 5
Women: BMR = 10 × weight in kg + 6.25 × height in cm minus 5 × age minus 161
Second, it multiplies your BMR by an activity factor to estimate total daily energy expenditure (TDEE), which is the number of calories that keeps your weight steady. The factors are 1.2 for sedentary, 1.375 for light activity, 1.55 for moderate, 1.725 for active and 1.9 for very active.
Worked example. A 30 year old woman, 175 cm tall and weighing 75 kg: 10 × 75 = 750, plus 6.25 × 175 = 1,093.75, minus 5 × 30 = 150, minus 161. Her BMR is about 1,533 calories. With moderate activity (× 1.55) her maintenance estimate is about 2,376 calories a day, the figure in the table above.
| Age | Male | Female |
|---|---|---|
| 20 | 2,711 cal | 2,453 cal |
| 30 | 2,633 cal | 2,376 cal |
| 40 | 2,556 cal | 2,298 cal |
| 50 | 2,478 cal | 2,221 cal |
| 60 | 2,401 cal | 2,143 cal |
Choosing your activity level honestly
The activity setting has a bigger effect on the answer than most people expect. Moving from moderate to active adds close to 300 calories to the estimate. People tend to rate themselves higher than their week really is, so base the choice on your typical week, including a desk job and rest days, not your best week. If you are between two levels, pick the lower one, then adjust using real results.
The activity factors already include normal exercise. If you use this estimate to set a daily target, you do not need to add the calories burned in a workout on top, because that would count the same exercise twice.
Using the number in practice
Body fat stores roughly 7,700 calories per kilogram (about 3,500 per pound). A daily gap of 500 calories therefore adds up to around 3,500 calories a week, or about 0.45 kg (1 lb). That is a useful rule of thumb rather than a promise. Your body adjusts as weight changes, water weight moves from day to day, and the estimate itself can be off by a few hundred calories in either direction.
A sensible approach is to follow the number for two to three weeks, track your weight on a regular schedule, and change the target by 100 to 200 calories if nothing is moving. Large, fast deficits are hard to sustain and are not recommended without medical supervision. If you are under 18, pregnant, managing a medical condition, or have a history of disordered eating, speak to a doctor or registered dietitian before changing how much you eat.
The BMR calculator shows the resting figure on its own, and the BMI calculator and ideal weight calculator give context for where your weight sits.
Why calorie calculators give different answers
Different tools use different equations. Mifflin-St Jeor is widely used for the general population. The older Harris-Benedict equation tends to give slightly higher results, and the Katch-McArdle equation uses lean body mass, so it suits people who know their body fat percentage. None of them measures your metabolism directly, so treat any single number as a starting point to test against your own results.
Frequently asked questions
How is my calorie need calculated?
We use the Mifflin-St Jeor equation, widely regarded as one of the more accurate formulas for estimating basal metabolic rate (BMR) — the calories your body burns at rest — then multiply it by an activity factor to estimate total daily energy expenditure.
How many calories should I eat to lose weight?
A commonly used guideline is a deficit of about 500 calories per day below maintenance, which tends to correspond to roughly 0.5kg (1lb) of weight loss per week — though individual results vary based on many factors.
Is this calculator accurate for everyone?
It's a population-level estimate, not a personalized medical calculation. Muscle mass, metabolic health conditions, and other individual factors can shift your actual needs. It's a reasonable starting point, not a precise prescription.
Should I consult a professional before changing my diet?
Yes — for any significant or sustained dietary change, especially involving a calorie deficit or surplus, a doctor or registered dietitian can help tailor a plan to your specific health situation.
How many calories does a moderately active person need per day?
For a 30-year-old at 175cm and 75kg, this calculator estimates about 2,633 calories/day for men and 2,376 for women at a moderate activity level (see chart above). Your own numbers will vary with age, height, and weight.
How many calories do I need to gain weight?
A common guideline is a surplus of about 500 calories/day above maintenance, corresponding to roughly 0.5kg (1lb) of weight gain per week — the "mild weight gain" figure this calculator shows automatically.
Is this a calorie calculator for weight gain, or just weight loss?
Both — enter your details above and this calculator shows your maintenance calories plus a mild weight-loss and a mild weight-gain target side by side, so it works as a calorie calculator for weight gain just as well as for weight loss.
How much of a calorie surplus do I need to bulk up?
A mild surplus of around 300-500 calories/day above maintenance is a common starting point for lean muscle gain without excessive fat gain. This calculator's "mild weight gain" figure uses a 500-calorie surplus — you can scale it down if you want a slower, leaner bulk.
Do calorie needs decrease with age?
Yes — this calculator's underlying formula reduces resting calorie needs by about 5 calories per year of age, reflecting the gradual decline in metabolism as we get older, holding height, weight, and activity level constant.
What is the difference between BMR and TDEE?
BMR is the energy your body uses at complete rest to keep you alive, such as breathing and circulation. TDEE (total daily energy expenditure) is BMR plus the energy used for movement, exercise and digesting food. This calculator shows TDEE as your maintenance calories.
Why do different calorie calculators give different results?
They use different equations (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle) and different activity multipliers. Differences of a few hundred calories are normal. Pick one and compare it against real changes in your weight over a few weeks.
Should I eat back the calories I burn exercising?
Not if you chose an activity level that already reflects your exercise. The multiplier averages your normal week, so adding workout calories on top counts the same activity twice. Only change the activity level if your routine changes.
How long should I follow my calorie target before adjusting it?
Two to three weeks of consistent tracking gives a clearer picture than day to day changes, which are mostly water. If your weight has not moved in the direction you want, change your target by about 100 to 200 calories and reassess.
How many calories are in a kilogram of body fat?
The common estimate is about 7,700 calories per kilogram (roughly 3,500 per pound). It is a rule of thumb, because your body adapts as you gain or lose weight, so real changes are usually slower than the arithmetic suggests over time.
Does this calculator work for teenagers?
The Mifflin-St Jeor equation was developed for adults, and growing teenagers have different energy needs. For anyone under 18, a doctor or registered dietitian is the right source for calorie guidance.
About this tool
This calculator estimates your daily calorie needs using the Mifflin-St Jeor equation, one of the most widely used formulas for estimating basal metabolic rate. It accounts for your age, sex, height, weight, and activity level to give a starting-point estimate for maintenance, weight loss, and weight gain calories.