Basal Energy Expenditure Calculator | Named REE Equations

Basal measurement uses controlled resting and post-absorptive conditions. Resting-energy prediction instead substitutes inputs into a regression equation. FAO/WHO/UNU definitions distinguish basal conditions and total expenditure. This form does not perform calorimetry.

Total daily expenditure includes energy beyond rest. A selected numerical product is not a measurement of that expenditure, a minimum food allowance, or a verified maintenance intake. There is no fixed percentage gap between the displayed equations.

Revised Harris–Benedict (Roza–Shizgal, July 1984): men: REE = 88.362 + 13.397 × W + 4.799 × H − 5.677 × A; women: REE = 447.593 + 9.247 × W + 3.098 × H − 4.330 × A. W is kg, H is cm and A is years; output is kcal/day. Original paper, Table 3, equations 3 and 6.

Mifflin–St Jeor (February 1990): men: REE = 10 × W + 6.25 × H − 5 × A + 5; women: REE = 10 × W + 6.25 × H − 5 × A − 161. W is kg, H is cm and A is years; output is kcal/day. Original paper, simplified equations.

The study included 498 healthy adults aged 19–78, including normal-weight and obese participants. This tool restricts Mifflin illustrations to 19–78; that range is not a guarantee of personal accuracy.

Katch–McArdle illustration: REE = 370 + 21.6 × lean body mass in kg. Joseph et al. (July–August 2017), equations section documents this expression. This is a bounded published illustration, not a claim that the original derivation or general validation has been established.

Select the equation explicitly. Body fat and BMI do not trigger an automatic recommendation. Katch requires entered body fat; no body-fat value is estimated or clamped. Mifflin is omitted from comparisons outside 19–78, while other retained equations keep their own educational interpretation.

Basal measurement uses controlled resting and post-absorptive conditions. Resting-energy prediction instead substitutes inputs into a regression equation. FAO/WHO/UNU definitions distinguish basal conditions and total expenditure. This form does not perform calorimetry.

Total daily expenditure includes energy beyond rest. A selected numerical product is not a measurement of that expenditure, a minimum food allowance, or a verified maintenance intake. There is no fixed percentage gap between the displayed equations.

Enter weight, height and age in the displayed units, then select the male or female coefficient set used in the source. These labels identify equation coefficients, not a measurement of body composition. Inputs must be complete finite numbers; results are cleared when contributing inputs change.

Metric inputs use kg and cm. Where imperial choices are present, pounds are multiplied by 0.45359237 and inches by 2.54 before calculation. Displayed kcal/day is rounded to a whole number.

At 70 kg, 175 cm and age 30, the male coefficients yield revised Harris–Benedict 1,695.667 kcal/day, Mifflin–St Jeor 1,648.75 kcal/day, and Katch with 20% body fat 1,579.6 kcal/day. Their disagreement is arithmetic, not a diagnosis or evidence of superiority.

The retained factors are 1.2, 1.375, 1.55, 1.725 and 1.9. Select a number to explore REE × factor. These choices are mathematical scenarios; an exercise frequency or job description does not establish an individual factor.

For a 70 kg, 175 cm, 30-year-old male coefficient example, Mifflin–St Jeor gives 1,648.75 kcal/day (displayed 1,649). Selecting 1.2 gives 1,978.5 kcal/day (displayed 1,979). Multiplication uses the unrounded equation result.

Equation output is predicted resting energy, not measured metabolism or a food-intake target. No automatic deficit, surplus, macronutrient prescription, weekly weight forecast, or medical metabolism grade is inferred.

A study population describes the evidence behind an equation. It does not establish suitability for every person with the same age or measurements, or for illness, pregnancy, lactation, or childhood. Individual nutrition decisions require information beyond these inputs.

The factors 1.2, 1.375, 1.55, 1.725 and 1.9 are site-defined mathematical scenarios. No cited source clinically validates them for an individual. Scenario = unrounded equation × selected factor.

Publication: Roza and Shizgal, July 1984, DOI 10.1093/ajcn/40.1.168. The retained coefficients come from Table 3, equations 3 and 6, based on 337 historical subjects including older adults. The paper reports limits for malnourished patients; its study statistics are not individual guarantees.

Historical context: Harris and Benedict (December 1918), original paper, page 373. The adult series had 136 men and 103 women. The tabulated ages 21–70 are not universal validation bounds. Sources checked on 2026-09-30.

Publication: Mifflin et al., February 1990, DOI 10.1093/ajcn/51.2.241. Original paper facsimile. Sources checked on 2026-09-30; this access date is separate from publication.

Publication: Joseph et al., July–August 2017, DOI 10.4103/ijem.IJEM_563_16. The study involved 30 professional male Asian-Indian weightlifters; all tested equations underestimated measured resting energy in that cohort. It does not establish universal superiority for athletes or the general population.

The cited textbook derivation was not independently reviewed. The 2017 date identifies this paper, not the original formula date. Sources checked on 2026-09-30.

NIST Handbook 44 (2026), Appendix C: 1 lb = 0.45359237 kg; 1 in = 2.54 cm.