TDEE vs BMR: which number to eat around

BMR is what you burn lying still; TDEE is what you burn living your day, and it is your maintenance number. Tables for four people at every activity level, what a BMR of 1,500 works out to, and whether eating below BMR is really off limits.

Sep 27, 2026 · By Calcelate Team

The short version: BMR is a building block, TDEE is the number you eat around. Eat at your TDEE and your weight holds. Eat below it and you lose. BMR is not a target for anything.

BMR, basal metabolic rate, is the energy your body uses at complete rest just to keep running — heart, lungs, brain, keeping warm. TDEE, total daily energy expenditure, is everything you burn in a day: the BMR plus digesting food, walking about, fidgeting and any exercise. TDEE is always the bigger of the two, and it is the one your weight responds to.

The difference in numbers

Calculators get from one to the other in two steps. First they estimate BMR from weight, height, age and sex, almost always with the Mifflin-St Jeor equation. Then they multiply it by a factor for how active you are.

Take the third row, a 30-year-old man of 75 kg (165 lb) and 178 cm (5 ft 10 in). His BMR is 1,718 kcal a day. His TDEE runs from 2,061 kcal if he sits all day to 3,263 kcal if he does physical work and trains on top of it. Same body, same BMR, and a difference of more than 1,200 kcal a day that comes entirely from the activity multiplier.

The multipliers also tell you how large a share BMR is. At 1.2 it is 83% of TDEE; at 1.9 it is 53%. For most people with a desk job and a few workouts a week, BMR is roughly three quarters of what they burn.

The equation comes from a 1990 study of 498 healthy adults whose resting energy use was measured directly. A systematic review for the American Dietetic Association found it the most reliable of the common equations, landing within 10% of measured resting rate for more people than any other — which also means some people fall outside that 10%.

If my BMR is 1,500, what is my TDEE?

Anywhere from 1,800 to 2,850 kcal a day, depending on the row you belong in. The range is wide because the multiplier does most of the work, and it is the part of the estimate you choose yourself.

Should I eat my BMR or my TDEE?

For maintenance, TDEE — that is literally what the number means. To lose weight, eat below TDEE by the size of deficit you want. BMR plays no direct part in either answer.

Eating at your BMR is not a special setting either. It is just a deficit that happens to equal the gap between the two numbers. For the man above, lightly active, that gap is 644 kcal a day, a fairly normal deficit. For the 60 kg (132 lb) woman in the first row, sitting most of the day, it is only about 260 kcal. The same advice — “eat your BMR” — produces a brisk diet for one of them and a slow one for the other.

Is it bad to eat below your BMR?

The rule “never eat below your BMR” is repeated all over fitness forums. It is not a physiological threshold. Nothing switches off when intake crosses BMR, because what you burn is your TDEE, and BMR is just one part of it. Eating below BMR simply means the deficit is larger than the gap between the two.

Where the rule does get in the way is for smaller people. The usual 0.5 kg (1.1 lb) a week target means eating about 550 kcal below maintenance, and for some bodies that is already under BMR.

The 60 kg woman lands on 1,248 kcal a day, 60 below her BMR, on the most ordinary weight-loss pace there is. The 2013 US guideline for managing overweight and obesity in adults typically prescribes 1,200 to 1,500 kcal a day for women and 1,500 to 1,800 for men — and 1,200 is below her BMR of 1,308. The same guideline reserves very-low-calorie diets, under 800 kcal a day, for medically supervised programs. That is below almost anyone’s BMR.

So the rule of thumb is a rough stand-in for something real, not the real thing. What deserves respect is the overall floor: under about 1,200 kcal a day for women or 1,500 for men is where calculators, this one included, start recommending medical supervision, and those are the numbers the guideline’s usual prescriptions begin at. Staying above BMR is not required to be safe, and it does not guarantee it either. A deficit that leaves you exhausted, hungry all day or losing strength is too big whatever its relation to BMR.

Why the activity multiplier overestimates

The multiplier is the weakest part of the calculation, for two reasons.

The steps are large. For the man above, moving from lightly to moderately active adds about 300 kcal a day — more than half of the 550 kcal deficit meant to produce 0.5 kg (1.1 lb) a week. Pick one level too high and most of a planned deficit disappears on paper.

And people tend to pick too high. In a study published in the New England Journal of Medicine, ten people who could not lose weight on what they reported as very low intakes were measured precisely. Their metabolism was normal. They had underreported their food by 47% on average and overreported their physical activity by 51%. That was a small, specific group, but the direction of the error is the one most calculators warn about.

Two habits keep the multiplier honest. When unsure between two levels, take the lower one. And do not add exercise calories from a tracker on top of a TDEE that already includes your training — that counts the same workout twice.

TDEE vs maintenance calories

They mean the same thing, from two directions. TDEE is the estimate: what a formula expects you to burn. Maintenance calories are what you can eat without your weight changing, and the only way to know that number exactly is to measure it on yourself.

Start with the estimate from the TDEE calculator, eat at it for two weeks, and compare the average weight of the second week with the first. Flat means you have found maintenance. Drifting down means your real TDEE is higher than estimated; drifting up means lower. Adjust by 100 to 200 kcal and repeat.

Maintenance also moves. A smaller body burns less, so as weight comes off TDEE comes down with it — a point Kevin Hall and colleagues modeled in The Lancet when they showed that weight loss slows over time on a constant intake. Recalculate every few kilos, and when you are ready to set a target below maintenance, the calorie deficit calculator turns it into a pace and a timeline.