TDEE Calculator

The calories your body burns at complete rest to run heart, brain, kidneys and other organs. Roughly 60–75% of your total daily burn.

Mifflin-St Jeor (1990) is the accuracy benchmark for the general population — within about 10% for most people who are not unusually lean or unusually large.

Male:   BMR = 10·kg + 6.25·cm − 5·age + 5
Female: BMR = 10·kg + 6.25·cm − 5·age − 161

Mifflin MD et al. Am J Clin Nutr. 1990;51(2):241–247.

Katch-McArdle uses lean body mass instead of total mass, so it is more accurate for lean, muscular or heavy-set people whose fat-to-muscle ratio deviates from average. This is why entering a body fat % changes the answer.

BMR = 370 + 21.6 · LBM (kg)
LBM = weight × (1 − body fat % / 100)

Cunningham has a steeper lean-mass coefficient. It tends to overestimate for the average person but fits highly-trained athletes better.

BMR = 500 + 22 · LBM (kg)

Cunningham JJ. Am J Clin Nutr. 1980;33(11):2372–2374.

Harris-Benedict (Revised) is the 1984 Roza & Shizgal revision of the 1919 original. Kept here for comparison; Mifflin generally beats it.

Male:   88.362 + 13.397·kg + 4.799·cm − 5.677·age
Female: 447.593 + 9.247·kg + 3.098·cm − 4.330·age

Roza AM, Shizgal HM. Am J Clin Nutr. 1984;40(1):168–182.

BMR multiplied by an activity factor covering movement (NEAT and exercise) and the thermic effect of food.

TDEE = BMR × activity multiplier

Activity multipliers are estimates, and real-world variance is high. Treat the output as a starting point, then adjust against two weeks of actual weight data. That correction matters more than which formula you picked.

Deficit and surplus

Target = TDEE × (1 + goal% / 100)
1 kg body fat ≈ 7,700 kcal

A 15–20% deficit is the usual sweet spot: fast enough to be motivating, slow enough to hold onto muscle. Past 25%, hunger, hormonal disruption and muscle loss all rise sharply — especially without high protein and resistance training.

Protein

Meta-analysis converges on 1.6–2.2 g/kg body weight for muscle protein synthesis in trained individuals. In a deficit, push toward the top of that range — or work from lean mass, which is what this calculator does once you give it a body fat %.

Morton RW et al. Br J Sports Med. 2018;52(6):376–384. Systematic review and meta-analysis of 49 studies.

Limits

Every formula here is a population estimate. Your actual metabolism can sit ±15% from any prediction, and the 12-week projection assumes a constant deficit that real life does not deliver — metabolic adaptation and water shifts both blur it.

This is not medical advice. If you are managing a health condition, or you are pregnant, work with a doctor or a registered dietitian rather than a calculator.