How the tdee calculator works
TDEE (total daily energy expenditure) is your basal metabolic rate multiplied by an activity factor:
The calculator offers three BMR equations (weight in kg, height in cm, age in years):
Harris-Benedict, revised 1984: men 88.362 + 13.397W + 4.799H − 5.677A; women 447.593 + 9.247W + 3.098H − 4.330A
Katch-McArdle: 370 + 21.6 × lean body mass (kg)
Mifflin-St Jeor is the default because studies have found it the most accurate of the common equations for most adults. Katch-McArdle uses lean mass, so it suits lean, muscular people who know their body fat percentage.
Goals add or subtract calories from TDEE: about 500 a day is roughly 1 lb (0.45 kg) a week. Macros use 1.6 g of protein per kg of body weight (0.73 g per lb), 25% of calories from fat, and the rest from carbohydrate (4 kcal per gram of protein or carbs, 9 per gram of fat).
Worked example
A 35-year-old man who is 5 ft 10 in (177.8 cm), weighs 180 lb (81.65 kg) and exercises 3 to 5 days a week:
TDEE = 1,758 × 1.55 ≈ 2,724 calories a day
To lose about 1 lb a week he would eat about 2,224 calories a day. At maintenance his macros would be about 131 g of protein (1.6 × 81.65), 76 g of fat (25% of 2,724 ÷ 9) and 380 g of carbohydrate. The revised Harris-Benedict equation gives a slightly higher BMR of about 1,837 for the same person.
Frequently asked questions
What is TDEE?
Total daily energy expenditure is the number of calories you burn in a day: your basal metabolic rate (energy used at rest) plus digestion, daily movement and exercise. Eating at your TDEE keeps your weight roughly stable.
How accurate is a TDEE calculator?
Equations like Mifflin-St Jeor predict resting metabolism within about 10% for most adults, and activity multipliers add more uncertainty. Treat the number as a starting point: track your weight for two to three weeks and adjust by 100 to 200 calories if it moves differently than expected.
How many calories should I eat to lose weight?
A deficit of about 500 calories a day below TDEE leads to roughly 1 lb (0.45 kg) of loss a week. Larger deficits work faster but are harder to sustain and can cost muscle. Most guidance suggests not going below about 1,200 calories a day for women or 1,500 for men without medical supervision.
Which BMR formula should I use?
Mifflin-St Jeor is the best general choice for most adults. Harris-Benedict tends to give slightly higher numbers. Katch-McArdle can be more accurate for lean or muscular people because it uses lean body mass, but only if your body fat estimate is reliable.
How do I pick my activity level?
Choose based on your whole week, not your best day. Most people with desk jobs who work out a few times a week fit 'lightly' or 'moderately active'. Overestimating activity is the most common reason calorie targets do not work.
How much protein do I need?
The calculator uses 1.6 g per kg of body weight (about 0.73 g per lb), a level research links to keeping or building muscle while dieting or training. The general minimum for adults is 0.8 g per kg. People with kidney disease should follow their doctor's advice.
Updated October 2026. Results are estimates for education, not financial or medical advice. All math runs in your browser; nothing you type is sent anywhere.