Free tool
BMR calculator
Your Basal Metabolic Rate is what you would burn lying still all day: breathing, circulating blood, keeping your organs running. It is the floor your calorie target is built on top of.
Updated
What BMR is, and isn’t
BMR accounts for somewhere around 60–70% of what most people burn in a day. It is not a target. Eating at your BMR means eating well below what you actually use.
The four numbers underneath are your BMR multiplied by each activity factor. One of them is your real maintenance level, and picking the right one matters more than the BMR figure itself.
This uses the Mifflin–St Jeor equation, which superseded Harris–Benedict as the standard because it is more accurate for modern body compositions.
Want maintenance calories directly? Use the TDEE calculator →
The equation
How BMR is calculated.
Mifflin–St Jeor takes weight, height, age and sex. Every term matters: muscle and organ mass scale with weight and height, and resting metabolism declines with age.
Men carry more lean mass on average at the same height and weight, which is why the constant differs. It is a population average, not a statement about any individual.
| Sex | Formula |
|---|---|
| Men | (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 |
| Women | (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161 |
Average BMR by age and sex
For a reference woman of 162 cm and 60 kg and a reference man of 175 cm and 75 kg. Every extra 10 kg of body weight adds roughly 100 kcal; every extra 10 cm of height adds about 60.
| Age | Women (60 kg, 162 cm) | Men (75 kg, 175 cm) |
|---|---|---|
| 20 | ~1,350 kcal | ~1,750 kcal |
| 30 | ~1,300 kcal | ~1,700 kcal |
| 40 | ~1,250 kcal | ~1,650 kcal |
| 50 | ~1,200 kcal | ~1,600 kcal |
| 60 | ~1,150 kcal | ~1,550 kcal |
| 70 | ~1,100 kcal | ~1,500 kcal |
The decline with age is real but gentle: about 50 kcal a decade from the equation alone. Most of what people experience as a “slowing metabolism” is lost muscle and less daily movement, both of which are at least partly reversible. Average BMR by age, explained →
BMR vs TDEE: which one do you eat?
Neither directly. BMR is the energy your body uses at complete rest. TDEE (total daily energy expenditure) adds everything else: walking, working, digesting, training. For most people TDEE is 1.2 to 1.7 times BMR.
Your calorie target for weight loss is set from TDEE, usually 10–20% below it. Eating at or below your BMR is a far larger deficit than it sounds and is hard to sustain. TDEE vs BMR explained →
Frequently asked questions
What does BMR mean?
BMR stands for basal metabolic rate: the number of calories your body burns in 24 hours at complete rest, just to keep you alive: breathing, circulation, temperature, brain and organ function. It is usually 60–70% of total daily burn.
What is a normal BMR?
Roughly 1,200–1,500 kcal for most women and 1,500–1,900 kcal for most men. Larger, taller, younger and more muscular people sit higher. There is no “good” BMR. It mostly reflects body size.
Should I eat my BMR to lose weight?
No. BMR is what you burn at rest, so eating at it means a very large deficit once normal daily movement is added. Set your target from TDEE instead, typically 300–500 kcal below it.
Why is my BMR lower than I expected?
BMR scales strongly with body size and lean mass. Shorter, lighter and older people have lower BMRs, and that is normal rather than a sign of a slow metabolism. Actual variation between people of the same size is usually within about 10%.
Does dieting permanently lower my BMR?
BMR falls as you lose weight, mostly because there is less of you to maintain. There is also a modest adaptive component during a deficit that largely recovers when you return to maintenance. Keeping protein high and training helps preserve the lean mass that drives BMR.
Mifflin–St Jeor or Harris–Benedict?
Mifflin–St Jeor. Harris–Benedict dates from 1919 and tends to overestimate for people who are not lean. Katch–McArdle can be better if you know your body fat percentage accurately. You can estimate that with the body fat calculator.
Next step
Knowing the number is the easy half.
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