Calorie Intake Calculator (Simple) | Educational REE Scenarios
Calculate Mifflin–St Jeor resting-energy arithmetic for ages 19–78 and selected multiplier scenarios.
Disclaimer: For informational purposes only. Not a substitute for professional medical advice. Always consult a healthcare provider for health-related decisions.
Calorie Intake Calculator (Simple)
Table of Contents
How the calculator works
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.
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.
Numeric multiplier scenarios
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.
Calorie goals and this tool
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.
Weight management and evidence limits
Resting-energy arithmetic alone does not establish an individual weight-management plan. A fixed subtraction cannot verify safety or a weekly rate of change. This form therefore reports the named resting estimate and selected scenario, without automatic diet targets.
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.
Macronutrients are outside this calculation
The Mifflin equation predicts resting energy from weight, height, age and a coefficient set. It does not calculate protein, carbohydrate or fat requirements. No percentage split or grams-per-kilogram target follows from its output.
Changing the selected multiplier changes only the numerical scenario; it does not establish nutritional adequacy.
Frequently Asked Questions
Does this measure my metabolism?
No. The output comes from a named equation, using the values entered. Indirect calorimetry is a different measurement process.
Which equation is best for me?
This tool does not rank equations for an individual. Different coefficients and research populations can produce different predictions without proving which prediction is closest to a measurement.
Should I eat the displayed number of calories?
The results are educational equation values and, where available, selected multiplier scenarios. They do not prescribe food intake or forecast weight change.
Why does changing an input remove the result?
A displayed result belongs to the inputs submitted. Editing a contributing field clears it so an old result is not mistaken for a new calculation.
Sources and interpretation
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: 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.
NIST Handbook 44 (2026), Appendix C: 1 lb = 0.45359237 kg; 1 in = 2.54 cm.