BMR Calculator: how many calories you burn at rest.
Enter your sex, age, height and weight. Get your basal metabolic rate from the three equations people use, each labeled.
Your resting energy
BMR, Mifflin St Jeor
1,330kcal
The main result. It is what you burn at rest, not your calories for the day.
Mifflin 1990BMR is resting energy only. For your calories on a rest day and a training day, use the maintenance calories calculator.
Hand it to your AI
Your AI can check these numbers against your training and adjust them. The prompt has your results filled in.
See the prompt
I'm a 35 year old woman, 168 cm and 62 kg. A BMR calculator gave me a resting energy of about 1,330 kcal a day (Mifflin St Jeor), 1,390 kcal (Harris Benedict revised). Use it in Memory.fit to set my daily calorie targets, with my training on top for each day of this week.
Gemini, Grok Bot, Dots, Muse and Cue: copy the prompt and paste it in.
With Memory.fit, your AI would use your resting energy to set calories for each day.
On Android now: get it on Google Play. One email when the iPhone app is on the App Store.
How it works
How the BMR Calculator works.
Your basal metabolic rate (BMR) is the energy your body uses at complete rest: breathing, circulation, keeping warm, repairing tissue. It is the floor under your day, not the whole day. Training and daily movement come on top of it.
This calculator shows three equations side by side. Mifflin St Jeor (1990) is the main one: it is the equation the Memory.fit engine uses, and it predicted resting energy best in the study that introduced it. The revised Harris Benedict (Roza and Shizgal, 1984) is the older standard and is still common in calculators. Cunningham needs your body fat percentage, because it works from fat free mass alone. In a study of recreational athletes (ten Haaf and Weijs, 2014) it predicted resting energy most often within range, better than Mifflin St Jeor, so it is worth adding if you know your body fat.
BMR is an estimate. Measured resting energy differs by about 10% between people with the same body. To get from BMR to what you eat in a day, use the maintenance calories tool, which adds daily life and your training and gives a rest day and a training day.
The formula
- Mifflin St Jeor (women) = 10 × kg + 6.25 × cm − 5 × age − 161
- Mifflin St Jeor (men) = 10 × kg + 6.25 × cm − 5 × age + 5
- Harris Benedict revised (women) = 447.593 + 9.247 × kg + 3.098 × cm − 4.330 × age
- Harris Benedict revised (men) = 88.362 + 13.397 × kg + 4.799 × cm − 5.677 × age
- Cunningham = 500 + 22 × fat free mass in kg
The science
Where the numbers come from.
These are the same rules Memory.fit's engine uses when your AI asks it for a number, read from one registry of cited sources.
Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition 51(2):241-247.
Research article · 1990 · doi:10.1093/ajcn/51.2.241
Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. American Journal of Clinical Nutrition 40(1):168-182.
Research article · 1984 · doi:10.1093/ajcn/40.1.168
Cunningham JJ. A reanalysis of the factors influencing basal metabolic rate in normal adults. American Journal of Clinical Nutrition 33(11):2372-2374.
Research article · 1980 · doi:10.1093/ajcn/33.11.2372
ten Haaf T, Weijs PJM. Resting energy expenditure prediction in recreational athletes of 18-35 years: confirmation of Cunningham equation and an improved weight-based alternative. PLoS ONE 9(10):e108460.
Research article · 2014 · doi:10.1371/journal.pone.0108460
Example
A worked example.
A 35 year old woman, 168 cm and 62 kg, with 25% body fat.
- 1Mifflin St Jeor: 10 × 62 + 6.25 × 168 − 5 × 35 − 161 = 1,334 kcal, shown as about 1,330.
- 2Harris Benedict revised: 447.593 + 9.247 × 62 + 3.098 × 168 − 4.330 × 35 = about 1,390 kcal.
- 3Cunningham: fat free mass is 62 × 0.75 = 46.5 kg, so 500 + 22 × 46.5 = about 1,520 kcal.
- 4The first two land about 60 kcal apart; Cunningham is higher because it reads her fat free mass directly. Gaps like this are normal: they are the equations' own error, about the size real people differ by.
Questions
BMR Calculator: questions.
Basal metabolic rate: the calories your body burns at complete rest. It is the largest part of what most people burn in a day, but not all of it.
BMR is resting energy only. TDEE, total daily energy expenditure, adds daily movement and training. For an athlete TDEE is different on a rest day and a training day, so use the maintenance calories tool for it.
Mifflin St Jeor is the usual choice for healthy adults. For recreational athletes, one study found Cunningham predicted resting energy most accurately, so it is worth a look if you know your body fat. All of them are estimates with an error of about 10%.
BMR is not a calorie target. It leaves out training and daily life, so eating only that would under fuel most athletes. Use your calories for the day instead.
Yes. Fat free mass uses more energy at rest than fat, which is why a body fat percentage makes the Cunningham result more personal. The effect per kilogram is modest.
Not medical advice. These numbers come from published research on groups of athletes. Your own needs can differ; talk to a doctor or a sports dietitian about any health condition.