Calorie Calculator

Estimate your daily calorie needs (TDEE) from age, sex, height, weight, and activity level using the Mifflin-St Jeor equation, with targets for losing or gaining weight.

How to use the calorie calculator

Enter your age, sex, height, weight, and activity level in metric or imperial units. The calculator estimates your Basal Metabolic Rate and your Total Daily Energy Expenditure — the calories you need to maintain your current weight — plus target intakes for losing or gaining weight at a steady, sustainable pace.

Maintenance, deficit, and surplus

Your TDEE is the balance point: eat that many calories and your weight stays roughly stable. Eating consistently below it creates a deficit and you lose weight; eating above it creates a surplus and you gain. The commonly used figure of a 500-calorie daily deficit corresponds to about half a kilogram of loss per week, which most people can maintain without feeling deprived.

Why it is an estimate, not a rule

No formula can capture your metabolism exactly. The Mifflin-St Jeor equation used here is well regarded for accuracy, but factors like muscle mass, sleep, stress, and how much you fidget all shift the real number. Treat the result as a well-informed starting point: eat at the suggested level for two or three weeks, weigh yourself regularly, and adjust. This tool is for general information and is not medical or dietary advice.

Frequently Asked Questions

How are daily calorie needs calculated?

This tool uses the Mifflin-St Jeor equation to estimate your Basal Metabolic Rate (BMR), then multiplies it by an activity factor to get your Total Daily Energy Expenditure (TDEE) — the calories you burn in a typical day including movement and exercise.

What is the difference between BMR and TDEE?

BMR is the energy your body uses at complete rest just to stay alive — breathing, circulation, cell repair. TDEE is BMR plus everything else you do: walking, working, exercising, even digesting food. TDEE is the number that matters for maintaining, losing, or gaining weight.

How many calories should I eat to lose weight?

A deficit of about 500 calories per day below your TDEE leads to roughly 0.5 kg (about 1 lb) of weight loss per week, since a kilogram of fat stores roughly 7,700 calories. Very aggressive deficits are hard to sustain and risk losing muscle, so a moderate deficit is usually best.

Why does activity level change the result so much?

The activity multiplier ranges from 1.2 for sedentary to 1.9 for very active, so it can swing your TDEE by hundreds of calories. Be honest about your typical week rather than your best week — most people overestimate. If unsure, pick the lower option and adjust based on real results.

How accurate is this calorie estimate?

The Mifflin-St Jeor equation is one of the most accurate general formulas, but every estimate is a starting point. Real needs vary with body composition, genetics, and non-exercise movement. Use the number as a baseline, track your weight over a few weeks, and adjust intake up or down based on what actually happens.

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