TDEE Calculator: BMR & Maintenance Calories (Mifflin-St Jeor)

Your TDEE is your estimated daily calorie burn: your BMR, the calories you burn at rest, multiplied by an activity factor from 1.2 to 1.9. This calculator uses the Mifflin-St Jeor equation, which a 2005 review found the most reliable common formula.

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Estimated daily calories (TDEE)
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How the tdee & bmr calculator works

This TDEE calculator estimates two numbers. BMR (basal metabolic rate) is the energy your body uses at complete rest for breathing, circulation and brain activity. TDEE (total daily energy expenditure) adds everything else you do and is a good estimate of your maintenance calories.

BMR uses the Mifflin-St Jeor equation, published in 1990 from measurements of 498 healthy adults: men = 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5; women = the same minus 161 instead of plus 5. A 2005 systematic review found it more likely than other common equations to land within 10% of measured resting rate. For a 30-year-old man at 180 lb and 5'10", BMR is about 1,783 calories.

TDEE multiplies BMR by an activity factor: 1.2 (sedentary), 1.375 (light), 1.55 (moderate), 1.725 (very active) or 1.9 (extra active). The same man at moderate activity lands at about 2,763 calories a day.

Activity level is where most estimates drift, because training three times a week doesn't make the rest of a desk-based week active. Use your result as a starting point, track your weight for two to three weeks and adjust from there.

How it works

BMR (basal metabolic rate) is the energy your body uses at complete rest: breathing, circulation, brain activity. TDEE (total daily energy expenditure) adds everything else you do.

The math (Mifflin-St Jeor): men = 10 x kg + 6.25 x cm - 5 x age + 5; women = 10 x kg + 6.25 x cm - 5 x age - 161. TDEE = BMR x an activity factor from 1.2 (sedentary) to 1.9 (very active).

What the research says

  • Mifflin, St Jeor et al. (1990) developed the equation from 498 healthy adults. Read the study
  • A systematic review found Mifflin-St Jeor the most reliable common equation, more likely than the other equations tested to land within 10% of measured resting rate (Frankenfield et al., 2005). Read the study

Glossary

BMR / RMR
Calories burned at rest. RMR is the practical, slightly less strict version.
TDEE
Your estimated total daily calorie burn.
Activity factor
A multiplier that scales BMR up for daily movement.
kcal
Kilocalorie, the 'calorie' on food labels.

Frequently asked questions

What is TDEE?

Total daily energy expenditure: an estimate of all the calories you burn in a day, calculated here as BMR multiplied by an activity factor.

What's the difference between BMR and TDEE?

BMR is the energy you burn at complete rest. TDEE adds daily movement and exercise on top, so it's always higher than BMR.

Which BMR formula is most accurate?

A 2005 systematic review found Mifflin-St Jeor more likely than other common equations to predict resting metabolic rate within 10% of measured values.

What activity level should I choose?

Think about your whole week, not just workouts. Most people with desk jobs who train 3 to 5 times a week fit 'moderate' (1.55) or 'light' (1.375).

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Sources
  1. Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247. https://pubmed.ncbi.nlm.nih.gov/2305711/
  2. Frankenfield D, et al. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005;105(5):775-789. https://pubmed.ncbi.nlm.nih.gov/15883556/
  3. Activity factors (1.2 to 1.9) are the conventional multipliers used with resting-rate equations; the TDEE is an estimate.

For information only, not medical advice.