Which formula is most accurate?

Mifflin-St Jeor is the modern default. Katch-McArdle needs your body-fat percentage and is best for lean people who know it.

How do I convert kcal to kJ?

Multiply by 4.184. Use the kcal/kJ toggle to view every result in either unit.

Why is 500 kcal/day the standard deficit?

About 3,500 kcal approximates 0.45 kg (1 lb) of body fat, so a 500 kcal daily deficit is roughly 0.45 kg per week.

Calorie Calculator

Estimate BMR and total daily energy expenditure with Mifflin-St Jeor, revised Harris-Benedict and Katch-McArdle (when body fat is known), then see calorie or kilojoule targets for maintenance and weight change.

Example values are shown — change any of them and the answer updates live.

Current age

years

Height

Weight

Activity level

Goal

Weekly rate

kg / week

TDEE — total daily burn

BMR — resting burnTDEE — total daily burn

How the target is computed

Step 1 · Resting burn (Mifflin-St Jeor)

BMR = 10·W + 6.25·H − 5·A + s

10×80 + 6.25×180 − 5×30 + 5

1,780 kcal

Step 2 · Activity-adjusted daily burn

TDEE = BMR × activity

× 1.55

2,759 kcal

Step 3 · Deficit for the weekly goal

deficit = weekly kg × 7700 ÷ 7

0.5 × 7700 ÷ 7

550 kcal

Informational screening only — not a medical diagnosis.

How the target is computed

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