TDEECalculatorMifflin-St Jeor Calculator
See your resting burn from the Mifflin-St Jeor equation, with your own numbers worked through the formula.
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Short answer
The Mifflin-St Jeor equation estimates your resting burn (BMR) from your weight, height, age and sex. For men it's 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5. For women it's the same with −161 at the end. In a review of the four most-used equations, it came within 10% of measured resting burn for more people than any other, so it's the best starting point when you don't know your body fat.
The equation
- Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Working in pounds and inches? Use 4.536 × weight (lb) + 15.88 × height (in) − 5 × age, then +5 for men or −161 for women. It gives the same answer, because it's just the metric version with the unit conversions built in.
Worked example
Take a 35-year-old woman who is 5 ft 5 in and 160 lb. In metric that's 165.1 cm and 72.6 kg.
| Step | Calories |
|---|---|
| 10 × 72.6 kg | 726 |
| + 6.25 × 165.1 cm | 1,032 |
| − 5 × 35 years | −175 |
| − 161 (women) | −161 |
| BMR | 1,422 |
That's what her body burns at complete rest. To get her daily total (TDEE), multiply by an activity level. If she exercises 1 to 3 days a week (Light, 1.375), she burns about 1,955 calories a day. The calculator above does both steps and shows your own numbers in the formula.
Where the equation comes from
Mark Mifflin, Sachiko St Jeor and colleagues published it in 1990. They measured resting burn with indirect calorimetry, a test that works out calories burned from the oxygen you breathe in and the carbon dioxide you breathe out, in 498 healthy adults aged 19 to 78: 247 women and 251 men, 264 of normal weight and 234 with obesity. Weight, height and age together explained 71% of the differences between people.
In the same group, the older Harris-Benedict equations from 1919 overestimated measured resting burn by about 5%. That's one reason we use Mifflin-St Jeor instead.
How accurate is it?
"Within 10%" is the usual test: does the equation land within 10% of what a lab measures? Here's how Mifflin-St Jeor has done in the studies we trust most.
| Who was tested | Within 10% of measured |
|---|---|
| Adults without obesity (the best study in the 2005 review) | 82% |
| 337 community adults: without obesity | 87% |
| Same study: with obesity | 75% |
| 90 recreational athletes | Under 50% |
So for most adults it's close, and its misses go both ways: in the 2005 review's best study, 10% of people were overestimated by more than 10% and 8% were underestimated. In the 337-person study it showed no overall lean in either direction, while most other equations ran high. The review also warned that older adults and US ethnic minorities were underrepresented in the research, and that errors for one person can still be large.
Who it fits less well
The equation only knows your weight, not what that weight is made of. Lean mass burns more than fat, so it struggles at the extremes.
- Very muscular or very lean people. In a group of recreational athletes who trained about 9 hours a week, it was within 10% for fewer than half. A 2023 review of 29 studies in athletes also found its average estimate was off. If you know your body fat, the Katch-McArdle calculator uses your lean mass instead.
- People with obesity. Accuracy drops to about 3 in 4 people. It's still a reasonable start, but your own weigh-ins matter more.
- Older adults. They were a smaller part of the research behind it, so treat the number as rougher.
Whoever you are, the fix is the same. Eat to your number for 2 to 3 weeks, compare your weekly average weight, and adjust by 100 to 200 calories if it's moving the wrong way.
Mifflin-St Jeor or another formula?
| Formula | Needs | Use it when |
|---|---|---|
| Mifflin-St Jeor (1990) | Weight, height, age, sex | You don't know your body fat. The default for most adults. |
| Katch-McArdle | Weight and body fat % | You have a body fat number you trust and you're lean or muscular. |
| Harris-Benedict (1919) | Weight, height, age, sex | Mostly historical. It ran about 5% high in the Mifflin study. |
Common questions
Is Mifflin-St Jeor BMR or RMR?
Strictly, it predicts resting energy expenditure (RMR), measured under slightly looser conditions than a true BMR test, so it usually reads a little higher. Calculators, including this one, treat the two as the same.
Why is the women's version 166 calories lower?
That gap comes from the sex term in the original study's math. Much of the difference between men and women of the same size is lean mass: in the same study, fat-free mass was the best single predictor of resting burn.
Does it work if I have a lot of weight to lose?
Yes, as a starting point. In a study of 337 adults it was within 10% for 75% of people with obesity, compared with 87% of those without. Check it against your weigh-ins after 2 to 3 weeks.
How often should I recalculate?
Every 10 to 20 lb (5 to 10 kg) you lose or gain, or every 4 to 6 weeks. Your weight is in the formula, so your BMR drops as you lose.
More calculators
Not medical advice. These numbers are estimates for healthy adults aged 18–80, based on published equations. They aren't reviewed by a doctor or registered dietitian. Talk to one before making big changes to how you eat, especially if you're pregnant or breastfeeding, under 18, have a history of disordered eating, have a medical condition, or take medication that affects appetite or weight. Medical disclaimer
Written by Peter Kohout, strength & conditioning coach
Sources
- Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr, 1990.
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc, 2005.
- Academy of Nutrition and Dietetics Evidence Analysis Library. Energy expenditure: prediction accuracy of the Mifflin-St Jeor equation in non-obese adults.
- Frankenfield DC. Bias and accuracy of resting metabolic rate equations in non-obese and obese adults. Clin Nutr, 2013.
- ten Haaf T, Weijs PJM. Resting energy expenditure prediction in recreational athletes of 18–35 years. PLoS One, 2014.
- O'Neill JER, Corish CA, Horner K. Accuracy of resting metabolic rate prediction equations in athletes: a systematic review with meta-analysis. Sports Med, 2023.
You're a 30-year-old man, 5 ft 10 in and 180 lb, moderately active.
You burn about
2,763
calories a day
Likely range 2,490–3,040 · 19,341 a week
This already counts your workouts, so don't add your watch's exercise calories on top.
for a more accurate number.
Your goal
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