Calculate your exact daily calorie needs to maintain, lose, or gain weight based on your unique body metrics.
Maintain Weight
--
Calories / Day
Lose Weight
--
0.5 kg / week
Gain Weight
--
0.5 kg / week
How are calories calculated?
This calculator uses the highly accurate Mifflin-St Jeor Equation to determine your Basal Metabolic Rate (BMR), which is the number of calories your body burns at rest. We then apply your activity level multiplier to determine your Total Daily Energy Expenditure (TDEE). To lose weight, a standard deficit of 500 calories per day is applied.
Last updated: July 2026
How Your Daily Calorie Needs Are Calculated
This calculator estimates your daily calorie needs in two steps. First, it calculates your Basal Metabolic Rate (BMR) — the energy your body burns just staying alive at rest — using the Mifflin-St Jeor equation, based on your age, sex, height, and weight. Then it multiplies that number by an activity factor to reach your maintenance calories, the number of calories that would keep your weight roughly stable.
A Worked Example
A 30-year-old man who is 5'10" (178 cm) and 160 lbs (72.5 kg), with a moderately active lifestyle, has an estimated BMR of about 1,673 calories. Multiplying by the moderate activity factor of 1.55 gives a maintenance level of roughly 2,593 calories per day. To lose about a pound a week, this calculator would suggest around 2,093 calories; to gain at the same pace, around 3,093 calories.
Understanding the Activity Multipliers
Sedentary (1.2): little to no exercise, mostly desk-based days
Lightly Active (1.375): light exercise or sports 1–3 days a week
Moderately Active (1.55): moderate exercise 3–5 days a week
Very Active (1.725): hard exercise 6–7 days a week
Extra Active (1.9): very intense daily training or a physically demanding job
Most people overestimate their own activity level — if you're unsure, it's usually safer to round down to the lower category, then adjust based on how your weight actually trends over the following weeks.
A Note on Safety
This tool gives you a mathematical estimate, not personalized medical or nutrition advice. Individual factors like medical conditions, medications, and body composition can shift what's right for you. Most guidelines advise against sustained intakes below roughly 1,200 calories a day for women or 1,500 for men without medical supervision. If you're considering a significant or aggressive change to your eating pattern, a doctor or registered dietitian can help make sure it's done safely.
Frequently Asked Questions
This calculator first estimates your Basal Metabolic Rate (BMR) — the calories your body burns at rest — using the Mifflin-St Jeor equation, one of the most accurate published formulas for this. It then multiplies your BMR by an activity factor based on how often you exercise, giving your maintenance calories (also called TDEE, or Total Daily Energy Expenditure).
One pound of body fat is roughly equal to 3,500 calories. Eating 500 fewer calories per day creates a weekly deficit of about 3,500 calories, which works out to roughly 1 pound (0.5 kg) of weight loss per week — a commonly recommended, gradual pace. The same logic applies in reverse for the 500-calorie surplus shown for weight gain.
It's a useful approximation, not an exact science. As you lose weight, your body's calorie needs actually decrease slightly (since a lighter body burns less energy), so real-world weight loss tends to slow down over time even at a consistent calorie deficit. Treat these numbers as a starting point to adjust from, not a guaranteed outcome.
They use the same underlying formula — this calculator is built specifically around the weight loss and weight gain use case, showing your maintenance calories alongside ready-made deficit and surplus targets. If you just want your raw Total Daily Energy Expenditure number without the weight-change framing, the TDEE Calculator gives you that directly.
No. The Mifflin-St Jeor equation only uses your age, sex, height, and weight — it doesn't distinguish between muscle and fat, so two people with the same stats but very different body compositions will get the same estimate here, even though their actual calorie needs may differ somewhat.
Most health guidelines advise against going below roughly 1,200 calories per day for women or 1,500 for men without medical supervision, since very low intakes can be difficult to sustain and may not provide adequate nutrition. If your calculated deficit target falls near or below that range, it's worth talking to a doctor or registered dietitian before proceeding.
The Mifflin-St Jeor equation is considered one of the more accurate predictive formulas available, but it's still an estimate — individual metabolism, medical conditions, and body composition all cause real variation. Use the result as a starting point, then adjust based on how your actual weight changes over a few weeks.