BMR (basal metabolic rate) is the number of calories your body uses in a day at complete rest, just to keep you alive. It is the largest part of what you burn, usually 60–70% of the total, and it is the foundation every calorie target is built on.
People usually look it up for one of two reasons: to check whether their own number is normal, or to understand why they seem to burn less than they used to. This covers both.
Average BMR at a glance
For most healthy adults:
- Women: roughly 1,200–1,500 kcal a day
- Men: roughly 1,500–1,900 kcal a day
The spread within each group is mostly about body size. A tall, heavy person has more tissue to maintain than a short, light one. Sex matters because men carry more lean mass on average at the same height and weight.
Your own figure: BMR calculator.
BMR by age: women
Estimated with the Mifflin–St Jeor equation for a woman of 160 cm.
| Age | 55 kg | 65 kg | 75 kg |
|---|---|---|---|
| 20 | ~1,290 | ~1,390 | ~1,490 |
| 30 | ~1,240 | ~1,340 | ~1,440 |
| 40 | ~1,190 | ~1,290 | ~1,390 |
| 50 | ~1,140 | ~1,240 | ~1,340 |
| 60 | ~1,090 | ~1,190 | ~1,290 |
| 70 | ~1,040 | ~1,140 | ~1,240 |
BMR by age: men
Estimated with the Mifflin–St Jeor equation for a man of 175 cm.
| Age | 70 kg | 80 kg | 90 kg |
|---|---|---|---|
| 20 | ~1,700 | ~1,800 | ~1,900 |
| 30 | ~1,650 | ~1,750 | ~1,850 |
| 40 | ~1,600 | ~1,700 | ~1,800 |
| 50 | ~1,550 | ~1,650 | ~1,750 |
| 60 | ~1,500 | ~1,600 | ~1,700 |
| 70 | ~1,450 | ~1,550 | ~1,650 |
Two quick rules of thumb fall out of the equation: every 10 kg of body weight adds about 100 kcal, and every 10 cm of height adds about 60 kcal.
Does BMR really drop with age?
In the equation, yes: about 5 kcal a year, or 50 kcal a decade. That is a small number. Over thirty years it is 150 kcal a day, the equivalent of a cup of sweet chai and a biscuit.
The larger decline people notice usually comes from two other things:
Losing muscle. Adults who do not do any resistance training lose muscle gradually from their thirties onward, and faster after about 60. Muscle costs more energy to maintain than fat, so less of it means a lower BMR. Strength training slows or reverses this at any age.
Moving less. This does not show up in BMR at all. It shows up in TDEE, the total you burn in a day. A desk job, a car commute and fewer active hobbies can take several hundred calories a day out of total expenditure, far more than age-related BMR decline. People often attribute this to a “slower metabolism”. It is mostly a quieter day.
A large 2021 study of energy expenditure across the lifespan found that, after adjusting for body size and composition, metabolic rate was remarkably stable from about age 20 to 60 and declined only gradually after that. Midlife weight gain is mainly about intake and activity, not a metabolism that switched off at 40.
What counts as a “low” BMR?
There is no good or bad BMR. It mostly reflects how much of you there is.
A 155 cm, 50 kg woman in her fifties might have a BMR of 1,050 kcal. That is not a slow metabolism; it is a small body. The consequence is real, though: her calorie target for weight loss will be lower than a larger person's, and a generic “eat 1,500 calories” plan may barely create a deficit for her.
Actual variation between people of the same size, age and sex is usually within about 10%. Truly low metabolic rates do occur (most commonly from an underactive thyroid), and if you are gaining weight on an intake that is genuinely low, with other symptoms such as fatigue and feeling cold, it is worth asking a doctor.
How accurate are these numbers?
Mifflin–St Jeor is the most accurate of the common equations for the general population, and it gets within 10% of a measured BMR for most people. That still means a figure of 1,500 could be 1,350 or 1,650 for you specifically.
It is least accurate for very muscular people (it underestimates) and people with a lot of body fat (it can overestimate). If you know your body fat percentage, the Katch–McArdle equation, which uses lean mass directly, can be more accurate. You can estimate body fat with the Navy body fat calculator.
The practical answer to “how accurate?” is the same as for any calorie estimate: use it as a starting point, track your intake and weight for three weeks, and adjust from what actually happens.
How to use your BMR
Do not eat it. That is the common mistake.
BMR is what you burn lying in bed all day. Your actual daily burn (TDEE) is BMR multiplied by an activity factor, usually 1.2 to 1.7. Eating at your BMR means a deficit of several hundred calories a day that most people cannot sustain, and a target below BMR is rarely a good idea without medical supervision.
| Activity level | Multiply BMR by | Example: BMR 1,400 |
|---|---|---|
| Sedentary (desk job, little exercise) | 1.2 | 1,680 |
| Lightly active (1–3 workouts a week) | 1.375 | 1,925 |
| Moderately active (3–5 workouts) | 1.55 | 2,170 |
| Very active (6–7 workouts, active job) | 1.725 | 2,415 |
A sensible weight-loss target is 10–20% below that TDEE. See TDEE vs BMR for why the activity multiplier is the weakest part of the whole calculation.
Can you raise your BMR?
A little, in one reliable way: build or keep muscle. Each kilogram of muscle adds roughly 13 kcal a day at rest: modest per kilo, meaningful over years, and far more meaningful for strength, blood sugar and ageing well than for calories.
Things that do not raise BMR meaningfully: green tea, chilli, cold showers, specific meal timings, eating “little and often”. Their effects are either tiny or temporary.
The number that matters more
For weight loss, your BMR is interesting, but your intake is decisive. The same BMR supports weight loss or gain depending entirely on what you eat against it, and intake is the part you control.
That is what BetterCal is for: logging meals by typing or speaking them, so the intake side of the equation stops being a guess.
Log a meal the way you would write it down. BetterCal turns a plain sentence, spoken or typed, into calories and macros. Free to start.
Download BetterCal on the App Store · Get BetterCal on Google Play
Frequently asked questions
What is the average BMR for a woman?
Roughly 1,200–1,500 kcal a day. A 30-year-old woman of 160 cm and 65 kg has a BMR of about 1,340. Smaller and older women sit lower; taller and heavier women higher.
What is the average BMR for a man?
Roughly 1,500–1,900 kcal a day. A 30-year-old man of 175 cm and 80 kg has a BMR of about 1,750.
How much does BMR decrease with age?
About 50 kcal per decade from age alone, according to the Mifflin–St Jeor equation. Larger apparent declines usually come from losing muscle and moving less, both of which are at least partly within your control.
Is a BMR of 1,200 low?
Not for a smaller or older woman. It is typical. For a man or a larger woman it would be unusually low, and if it came from a measurement rather than an equation, it could be worth discussing with a doctor.
Should I eat below my BMR to lose weight?
Generally no. Set your target from TDEE, around 10–20% below it. That is usually still above BMR, and it is a deficit you can hold for months rather than weeks.
Related: BMR calculator · TDEE calculator · how many calories should I eat
