BMR Calculator
The calories your body burns at complete rest, by the three equations dietitians and coaches use, side by side with the working, and how far any of them can be off.
How active you are
Lightly active · 5,000–7,500 steps a day. A desk job with some walking, or 1–3 workouts a week. × 1.55
More optionsMifflin-St Jeor
From a body-composition scan or scale. It lets you use Katch-McArdle, which works from lean mass.
BMR equation
Why sex? The equations were fitted on people recorded as male or female, so they need one. If neither fits your body, try both: you are likely between the two.
ExampleA 35-year-old woman, 72 kg, 165 cm
1,420kcal a day
What your body burns at complete rest. Allow ±10%: about 1,270–1,560.
- Mifflin-St Jeor19901,420
- Harris-Benedictrevised 19841,470
- Katch-McArdlefrom lean massAdd your body fat % under More options to see it.
Shaded: within 10% of the equation you’re using. Mifflin-St Jeor lands within 10% of a measured BMR for more people than other equations.
- Maintenance (× 1.55)
- 2,190 kcal
- To lose 0.36 kg a week
- 1,800 kcal
General information from published research, not a diagnosis or medical advice. Talk to a doctor before changing medication or treatment. An estimate for adults, not for pregnancy or breastfeeding; if eating feels hard or stressful, talk to a doctor. Terms
Your maintenance caloriesAbout 2,190 kcal a day
- At rest (BMR)1,420
- Moving and exercise560
- Digesting food220
About 2,190 kcal a day, likely 2,020–2,370: your BMR of 1,420 × 1.55 for lightly active.
Calories for your goalTo lose 0.36 kg a week: 1,800 kcal a day
1,800 kcal a day · 400 below maintenance
65 kg in about 19 weeks. Maintenance moves with your weight: about 2,090 kcal at 65 kg, so re-check every few weeks.
The page never goes under 1,200 kcal for women or 1,500 for men, or faster than 1% of your weight (at most 1 kg) a week.
Your macros115 g protein · 200 g carbs · 60 g fat
Protein at 1.6 g/kg, where extra stopped adding muscle in trials; fat at 30% of calories; carbs the rest.
- Protein115 g26% of calories30 g a meal
- Carbs200 g44% of calories50 g a meal
- Fat60 g30% of calories15 g a meal
For 1,800 kcal a day. Aim for about 25 g of fibre too (14 g per 1,000 kcal).
How this works: Method, 9 sources, Checked against 4 worked examples,
How this works
Method
BMR, the basal metabolic rate, is the energy your body uses lying still and awake: breathing, circulation, keeping warm. None of the equations measure it; each was fitted to people whose resting rate was measured with indirect calorimetry, then predicts yours from what they found. Full method
Sources
- Frankenfield et al., Comparison of predictive equations for resting metabolic rate: a systematic review (J Am Diet Assoc, 2005)
- Mifflin et al., A new predictive equation for resting energy expenditure in healthy individuals (Am J Clin Nutr, 1990)
- Roza and Shizgal, The Harris Benedict equation reevaluated (Am J Clin Nutr, 1984)
- McArdle, Katch and Katch, Essentials of Exercise Physiology, 3rd edition (2006), p. 266
- Human energy requirements: report of a joint FAO/WHO/UNU expert consultation (FAO, 2004)
- 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults (Circulation, 2014)
- A meta-analysis of protein supplementation and resistance training (Morton et al.) (Br J Sports Med, 2018)
- ISSN position stand: protein and exercise (Jäger et al.) (J Int Soc Sports Nutr, 2017)
- Dietary Guidelines for Americans, 2020–2025, Appendix 1 (USDA and HHS, 2020)
How it’s tested
4 worked examples for this page are checked by automated tests before every release: given the inputs, the tool must show the expected answer.
Limits
General information from published research, not a diagnosis or medical advice. Talk to a doctor before changing medication or treatment. An estimate for adults, not for pregnancy or breastfeeding; if eating feels hard or stressful, talk to a doctor.
Changes
- First published: maintenance calories as a range, calories for your goal with a week-by-week timeline, macros and protein, with calorie, macro, BMR and protein calculator pages.
The three BMR equations, and which to trust
BMR, the basal metabolic rate, is the energy your body uses lying still and awake: breathing, circulation, keeping warm. None of the equations measure it; each was fitted to people whose resting rate was measured with indirect calorimetry, then predicts yours from what they found.
Worked example: a man of 42, 180 cm and 88 kg. Mifflin-St Jeor: 10 × 88 + 6.25 × 180 − 5 × 42 + 5 = 1,800 kcal. Revised Harris-Benedict: 88.362 + 13.397 × 88 + 4.799 × 180 − 5.677 × 42 = 1,892.7 kcal. If a scan put his body fat at 22%, his lean mass is 88 × 0.78 = 68.64 kg and Katch-McArdle gives 370 + 21.6 × 68.64 = 1,852.6 kcal. Three answers within about 5% of each other, which is normal.
Mifflin-St Jeor (1990) was built from 498 healthy adults aged 19 to 78, about half with obesity, and found the 1919 Harris-Benedict equations overestimated measured rates by 5%. Roza and Shizgal refitted Harris-Benedict in 1984 and put its precision at ±14%. A 2005 systematic review found Mifflin-St Jeor came within 10% of the measured rate for more people than the others, so it is the default here. Katch-McArdle ignores age and sex and works from lean mass alone, so it is only as good as your body-fat figure.
Mifflin-St Jeor: 10 × kg + 6.25 × cm − 5 × age + 5 (men) or − 161 (women)
- Mifflin-St Jeor was the most reliable of the common equations, predicting RMR within 10% of measured in more non-obese and obese people than any other, with the narrowest error range. Source: Frankenfield et al., Comparison of predictive equations for resting metabolic rate: a systematic review (J Am Diet Assoc, 2005).
- Derived from 498 healthy people aged 19–78 (247 women, 251 men); the original Harris-Benedict equations overestimated their measured REE by 5%. Source: Mifflin et al., A new predictive equation for resting energy expenditure in healthy individuals (Am J Clin Nutr, 1990).
- The Harris-Benedict equations estimate the resting energy expenditure of a normal subject with a precision of ±14%. Source: Roza and Shizgal, The Harris Benedict equation reevaluated (Am J Clin Nutr, 1984).
- Katch-McArdle: 370 + 21.6 × lean body mass in kg. Source: McArdle, Katch and Katch, Essentials of Exercise Physiology, 3rd edition (2006), p. 266.
BMR by age
kcal a day, rounded to 10, for a woman of 165 cm and 65 kg and a man of 178 cm and 80 kg. BMR falls with age in both equations.
| Age | Woman, Mifflin-St Jeor | Woman, Harris-Benedict | Man, Mifflin-St Jeor | Man, Harris-Benedict |
|---|---|---|---|---|
| 20 | 1,420 | 1,470 | 1,820 | 1,900 |
| 30 | 1,370 | 1,430 | 1,770 | 1,840 |
| 40 | 1,320 | 1,390 | 1,720 | 1,790 |
| 50 | 1,270 | 1,340 | 1,670 | 1,730 |
| 60 | 1,220 | 1,300 | 1,620 | 1,670 |
| 70 | 1,170 | 1,260 | 1,570 | 1,620 |
Frequently Asked Questions
What is a normal BMR?
For most adults somewhere around 1,200–1,600 kcal a day for women and 1,500–2,000 for men, depending mostly on size and age; the table shows how it falls with age at one height and weight. There is no “good” BMR: a bigger or younger body simply uses more.
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest. TDEE, total daily energy expenditure, adds everything else: walking, work, exercise and digesting food. Multiply your BMR by an activity multiplier (1.4 to 2.2 here) to get it.
Should I eat my BMR to lose weight?
No need to. The calories that matter are your maintenance (TDEE) and a deficit below it. Eating at your BMR is just one point on that scale, and for active people it can be a much bigger deficit than they need.
Can I raise my BMR?
A little, by adding muscle: fat-free mass was the best single predictor of resting energy in the Mifflin study, and it is what Katch-McArdle is built on. Strength training is how to build it.