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The Mifflin-St Jeor equation predicts resting energy from body measurements. It does not directly measure oxygen consumption or free-living energy expenditure.
Free TDEE calculator
Estimate daily energy needs with visible arithmetic.
Calculate predicted resting energy expenditure with the published Mifflin-St Jeor equation, then apply a conventional activity scenario. Use the result as a starting estimate, not a laboratory measurement.
No signup. Inputs stay in this browser.
Estimate TDEE
Choose the units and published equation constant that fit the calculation.
This calculation runs locally and sends no data.
Predicted resting energy
Estimated TDEE
Activity factor
Formula: resting energy = 10 × weight in kg + 6.25 × height in cm − 5 × age + the selected published constant. Estimated TDEE = resting energy × activity factor.
What this result means
An activity scenario
The multiplier lets you inspect a conventional scenario. Categories such as moderately active can be interpreted differently and are not personalized measurements.
A value to review
Compare the estimate with repeated intake and weight observations. Daily scale noise and incomplete food logs can distort short windows.
Public calculator, private product model
This tool intentionally uses a published equation and direct multiplication. It does not reproduce Forma’s adaptive TDEE system. Forma can update an in-app estimate from logged calorie intake and smoothed bodyweight change, but its equations, coefficients, thresholds, confidence logic, and recommendation rules remain proprietary. Read the public methodology and limitations.
Sources
Mifflin et al., 1990
The original resting-energy prediction equation, developed from 498 healthy adults aged 19 to 78.
Sabatoun et al., 2023
A critical appraisal showing why predicted resting energy varies across equations, populations, and comparison methods.
Activity factors on this page are conventional planning scenarios. They are not presented as values validated for every person.
Frequently asked questions
What is TDEE?
Total daily energy expenditure is the energy a person expends over a day. This calculator estimates it by multiplying predicted resting energy expenditure by a selected activity factor.
Is a TDEE calculator exact?
No. Prediction equations and activity multipliers are starting estimates. Individual error can be meaningful, and TDEE can change with body mass, activity, intake, and other factors.
Why does the equation ask for a published sex constant?
The original Mifflin-St Jeor equation publishes two sex-specific constants, plus 5 and minus 161. The choice is an equation input and is not an identity classification.
Is this calculator Forma’s adaptive metabolism model?
No. This page uses public arithmetic only. Forma’s in-app adaptive TDEE estimate uses logged calorie intake and smoothed bodyweight change, while its equations, coefficients, thresholds, and recommendation rules remain proprietary.
Turn a starting estimate into a connected record.
Track meals, calories, macros, steps, bodyweight trends, and training in Forma. For medical conditions, pregnancy, eating-disorder concerns, or individualized nutrition care, consult a qualified clinician.
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