| Goal | Calories / day | Rate |
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How your TDEE is calculated
Your total daily energy expenditure is built in two steps. First the calculator finds your basal metabolic rate (BMR) — the calories your body burns at complete rest — using the Mifflin-St Jeor equation, which dietitians regard as the most reliable formula from height, weight, age and sex. For men it is 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5; for women the final term is − 161 instead of + 5. Then it multiplies that BMR by an activity factor from 1.2 (sedentary) up to 1.9 (extra active) to account for movement, exercise and digestion. The result is your TDEE: the calories you need each day to hold your current weight. Want just the resting number on its own? Use the BMR Calculator.
Using TDEE to lose or gain weight
Weight change comes down to energy balance. Eat at your TDEE and your weight stays steady; eat below it and you lose, eat above it and you gain. Because a pound of body fat stores roughly 3,500 calories, a daily deficit of about 500 calories loses close to one pound a week — the “Lose weight” row in the table above. For a plan built around a specific deficit and goal weight, use the Calorie Deficit Calculator; to split your target calories into protein, carbs and fat, use the Macro Calculator.
Why the activity multiplier matters most
The BMR half of the formula is precise, but the activity multiplier is an estimate, and it is where nearly all the error lives. Two people with identical stats can have TDEEs hundreds of calories apart depending on how much they move outside the gym. Treat the number here as a well-chosen starting point: track your weight and intake for two to three weeks, and if the scale is not moving the way you expect, nudge your calories up or down by 100–200 rather than assuming the formula is wrong.