Calorie Needs Calculator

Method, assumptions & sources

Who this is for

Adults aged 20 or older, outside pregnancy and breastfeeding; educational estimates for generally healthy adults.

How it works

Mifflin: R = 10W + 6.25H − 5A + s, with s = −161 (female) or +5 (male). Revised Harris–Benedict: female R = 447.593 + 9.247W + 3.098H − 4.330A; male R = 88.362 + 13.397W + 4.799H − 5.677A. Katch–McArdle: R = 370 + 21.6 × W × (1 − body-fat%/100). W is kg, H cm, A years; result kcal/day. Daily expenditure = R × selected whole-day PAL. Six anchors (1.40, 1.55, 1.70, 1.85, 2.00, 2.20) sit within FAO published lifestyle ranges; they are not six independently validated activity prescriptions.

Keep in mind

• An estimate or population reference is not an individual diagnosis, treatment plan or prescribed target.
• Results may not apply to illness, unusual body composition, pregnancy or breastfeeding.
• Mifflin was derived in healthy adults aged 19–78; estimates outside the source population or with inaccurate body-fat inputs can have substantial error.
• Resting expenditure is not a recommended food intake. No weight-loss deficit or guaranteed outcome is generated.

Sources

• Mifflin et al. (1990): original resting-energy study (opens in a new tab)
• Roza & Shizgal (1984): Harris–Benedict revision (opens in a new tab)
• Tang et al. (2025): Katch–McArdle equation and prediction uncertainty (opens in a new tab)
• FAO/WHO/UNU: adult energy expenditure and whole-day PAL ranges (opens in a new tab)