TDEE & Calorie Calculator
TDEE — total daily energy expenditure — is the number of calories you burn in 24 hours including everything from digestion to workouts. It is the anchor every sensible plan hangs from: eat below it to lose weight, above it to gain. This calculator computes your BMR with the Mifflin-St Jeor equation (the formula most dietitians start from), then applies an honest activity multiplier you pick from five plain-language levels.
Two reference lines sit next to the maintenance number: a 500 kcal deficit for steady loss (about half a kilo a week) and a +300 kcal surplus for lean gain, because eating wildly past your TDEE mostly buys fat, not muscle. Your inputs are remembered on this device — recheck after your activity level changes and the whole picture updates in one tap.
How to use
- Enter sex, age, height and weight — your BMR appears immediately in the stats row.
- Pick the activity level that matches your real week, not your aspirational one — the big number is your maintenance calories.
- Use the −500 and +300 reference lines for loss or lean-gain plans, and share the estimate with one tap.
Frequently asked questions
How is TDEE calculated?
BMR × activity multiplier. BMR comes from the Mifflin-St Jeor equation (10 × weight kg + 6.25 × height cm − 5 × age + 5 for men, −161 for women); the multiplier runs from 1.2 for sedentary to 1.9 for athletes. The result is an estimate — treat it as a starting point and adjust against real weight trends.
Should I eat below my TDEE to lose weight?
A deficit is what produces fat loss, and 500 kcal below maintenance is the standard steady pace (≈0.5 kg/week). Going far below BMR is where diets backfire — energy, training and adherence all crumble. The loss line shows the moderate starting point, not a hard limit.
Why is my TDEE different from my friend's?
Body size, muscle mass, age and sex move BMR substantially — a heavier, younger, taller body burns more at rest. Two people with identical lifestyles can differ by 400+ kcal a day, which is exactly why shared diet numbers fail and personal calculators work.
How accurate is the Mifflin-St Jeor equation?
It lands within about 10% of measured resting metabolism for most adults and outperforms older equations in validation studies. Use the estimate to set a starting intake, then trust the scale trend over two weeks — if weight isn't moving as predicted, adjust intake by 100-200 kcal.