TDEE calculator

UNDERSTANDING YOUR NUMBERS

What is TDEE?

TDEE — Total Daily Energy Expenditure — is the total number of calories your body burns in a 24-hour period. It is the single most useful number in nutrition.

Unlike BMR, which only measures the calories your body needs at complete rest, TDEE accounts for everything: the energy cost of digesting food, keeping warm, walking to your kitchen, and every workout you do.

Eat consistently below your TDEE and you lose weight. Eat above it and you gain. Match it exactly and your weight stays stable. This relationship — called energy balance — is the foundational law of body composition, even when other variables like macronutrient ratios, meal timing, and sleep quality complicate the picture.

BMR~60–75%

Basal Metabolic Rate — the cost of being alive: breathing, organ function, cellular repair.

TEF~8–15%

Thermic Effect of Food — the energy used to digest, absorb, and metabolise what you eat.

EAT~5–10%

Exercise Activity Thermogenesis — calories burned during planned, deliberate exercise.

NEAT~10–20%

Non-Exercise Activity Thermogenesis — fidgeting, walking, standing. Highly variable person-to-person.

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NEAT is the most underappreciated component. Two people with identical BMRs and workout schedules can have TDEEs that differ by 500–800 kcal/day purely due to how much they fidget, pace, and move incidentally throughout the day.

METHODOLOGY

The Formulas

Four equations. Each with a different history, different assumptions, and different ideal use cases.

011990

Mifflin-St Jeor

The modern gold standard

Accuracy

Developed by MD Mifflin and ST St Jeor, this equation was derived from a study of 498 healthy adults. It consistently outperforms older equations in predicting resting metabolic rate and is the formula most recommended by dietitians today.

EQUATION
♂ Male(10 × kg) + (6.25 × cm) − (5 × age) + 5
♀ Female(10 × kg) + (6.25 × cm) − (5 × age) − 161
kgBody weight in kilograms
cmHeight in centimetres
ageAge in years
STRENGTHS
  • +Validated across large, diverse populations
  • +No body fat % measurement required
  • +Most accurate for average body compositions
LIMITATIONS
  • −Less accurate at extremes of body fat
  • −Does not account for lean mass directly
BEST FORMost people — general population

Nutritional Physiology & MPS

Nitrogen Balance & Hypertrophy

Protein intake is the primary driver of Nitrogen Balance. To remain in an anabolic state, nitrogen intake must exceed excretion. The 0.7g/lb baseline is the clinically observed "saturation point" where muscle protein synthesis is fully optimized.

The mTOR Pathway & Leucine

The Mammalian Target of Rapamycin (mTOR) pathway regulates cell growth. Leucine, a branched-chain amino acid, acts as the primary chemical trigger for this process. A high-protein environment ensures a consistent 2.5g+ Leucine spike per feeding cycle.

Thermic Effect of Food (TEF)

Protein requires significant metabolic energy to process. Approximately 20-30%of protein calories are burned during digestion, compared to > 10% for carbohydrates and fats, providing a metabolic advantage for body composition.

Bioavailability Metrics

This formula assumes consumption of high-quality sources with high Biological Value (BV) and PDCAAS scores, such as whey, eggs, or isolated plant proteins, to ensure effective amino acid absorption.

Clinical Literature

  • Phillips et al. (2011): Optimal protein for athletes.
  • Morton et al. (2018): Meta-analysis on 1.6g/kg limits.
  • Schoenfeld (2018): Protein timing and hypertrophy.
  • Helms et al. (2014): Protein needs in energy-restricted resistance-trained athletes.
SCIENTIFIC REFERENCES

Citations

Every formula and activity multiplier used in Calvor is derived from peer-reviewed research. The primary sources are listed below.

  1. 01
    Mifflin-St Jeor formula

    Mifflin, M.D., St Jeor, S.T., Hill, L.A., Scott, B.J., Daugherty, S.A., & Koh, Y.O. (1990). A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition, 51(2), 241–247.

    Derived BMR equations from 498 healthy adults aged 19–78. Found their equation predicted REE within 10% for 82% of subjects — outperforming the Harris-Benedict equation at the time.

    DOI10.1093/ajcn/51.2.241
  2. 02
    Harris-Benedict formula (original)

    Harris, J.A., & Benedict, F.G. (1919). A Biometric Study of Human Basal Metabolism. Proceedings of the National Academy of Sciences, 4(12), 370–373.

    The original foundational work establishing BMR equations for men and women based on height, weight, and age. Derived from a sample of 239 subjects. Standard reference for 70 years before revision.

    DOI10.1073/pnas.4.12.370
  3. 03
    Harris-Benedict formula (revised)

    Roza, A.M., & Shizgal, H.M. (1984). The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. The American Journal of Clinical Nutrition, 40(1), 168–182.

    Revised the original 1919 Harris-Benedict coefficients using a larger, more diverse sample. The revised equation is what most calculators implement today when referring to "Harris-Benedict".

    DOI10.1093/ajcn/40.1.168
  4. 04
    Katch-McArdle formula

    Katch, F.I., & McArdle, W.D. (1975). Prediction of body density from simple anthropometric measurements in college-age men and women. Human Biology, 47(3), 245–262.

    Established that lean body mass is the primary driver of resting metabolic rate, producing an equation that removes gender as an independent variable. Particularly accurate for lean and athletic populations.

  5. 05
    WHO / Schofield formula

    Schofield, W.N. (1985). Predicting basal metabolic rate, new standards and review of previous work. Human Nutrition: Clinical Nutrition, 39(Suppl 1), 5–41.

    Compiled and analysed BMR data from over 7,000 subjects across multiple countries, producing age-stratified equations. Adopted by the World Health Organization and FAO as the basis for international dietary energy recommendations.

  6. 06
    WHO / Schofield formula (official adoption)

    World Health Organization (1985). Energy and protein requirements: Report of a joint FAO/WHO/UNU expert consultation. WHO Technical Report Series, 724. Geneva: WHO.

    The WHO/FAO/UNU report that formally adopted Schofield's age-banded equations for international use in assessing dietary energy requirements across populations.

    URLhttps://www.who.int/publications/i/item/9241200731
  7. 07
    Activity multipliers (MET basis)

    Ainsworth, B.E., Haskell, W.L., Herrmann, S.D., et al. (2011). Compendium of Physical Activities: a second update of codes and MET values. Medicine & Science in Sports & Exercise, 43(8), 1575–1581.

    The standard reference for MET (Metabolic Equivalent of Task) values used in activity multiplier research. Provides the empirical basis for quantifying energy cost across hundreds of activities, underpinning the activity factors applied to BMR.

    DOI10.1249/MSS.0b013e31821ece12