Which TDEE Formula? Mifflin, Harris, Katch & Cunningham
TDEE calculators usually choose a resting-energy equation first, then apply an activity factor. The useful choice depends partly on which inputs you can supply reliably.
Compare resting-energy equations →Four equations, different inputs
| Equation | Inputs | What TDEE Calculator does |
|---|---|---|
| Mifflin–St Jeor | Weight, height, age, sex coefficient | Automatic choice without body fat |
| Revised Harris–Benedict | Weight, height, age, sex coefficient | Optional resting-energy comparison |
| Katch–McArdle | Weight and body-fat percentage | Automatic choice when body fat is supplied |
| Cunningham (RMR) | Weight and body-fat percentage | Optional fat-free-mass RMR comparison |
All four predict resting energy, not the energy cost of your whole day. Cunningham is labelled RMR because BMR and RMR have different measurement conditions. The activity factor can introduce more uncertainty after the resting estimate has been selected.
If you do not know your body-fat percentage
Start with the Mifflin–St Jeor calculator. It does not need body-fat data. Enter weight in kilograms or pounds, height in centimetres or inches, age and the equation’s sex coefficient. The calculator converts imperial measurements before applying the formula.
The binary sex coefficients come from the equation and do not describe everyone’s physiology or identity. If they are not useful for you, regard the output as approximate and seek individual guidance. Choosing a formula by whichever answer you prefer does not improve the estimate.
If you have a body-fat measurement
The Katch–McArdle calculator uses fat-free mass: weight × (1 − body-fat percentage ÷ 100). At 80 kg and 20% body fat, that is 64 kg. Katch gives 370 + 21.6 × 64 = about 1,752 kcal/day. Cunningham gives 500 + 22 × 64 = 1,908 kcal/day. Their difference reflects different models.
A five-percentage-point body-fat error at that weight changes Katch by about 86 kcal/day. Consumer scales, visual estimates and different measurement methods may disagree. A fat-free-mass formula is not automatically better because it asks for another input.
Choose once, then check the wider picture
Our BMR comparison tool lets you inspect all four equations. Keep the assumptions consistent while you compare, then select a realistic activity level. Follow intake and a longer weight trend before deciding that a new formula is necessary.
Formula choice is an estimation decision, not a medical assessment. These tools do not support children, pregnancy, breastfeeding or clinical nutrition treatment. References below describe the published equations; their authors do not endorse this site or its planning rules.
Methods & references
- Our equations, planning rules and scope
- Mifflin et al. (1990), resting energy expenditure
- Roza & Shizgal (1984), revised Harris–Benedict equation
- Cunningham (1980), body composition and basal metabolism
An informational tool; no medical review is claimed. Activity factors and caution thresholds are product planning conventions. Citations do not imply endorsement.