Maintenance Calorie Calculator

What maintenance actually means

Your maintenance calories are the amount you can eat in a day without your weight going anywhere. Eat that, and next month you weigh what you weigh now. It is the still point that every other calorie goal is measured from: a deficit is maintenance minus something, a surplus is maintenance plus something. Find this number and the rest of it stops being guesswork.

So you entered your age, sex, height, weight and how much you exercise, and the tool gave you a figure. That figure is a good place to start. But maintenance has a habit most calorie pages never mention: it does not stay still. It drifts, and it drifts most for exactly the people who care about it most, which is anyone who has recently lost weight. That is the real subject of this page.

The formula this calculator uses

Two steps. First your resting burn, using the Mifflin-St Jeor equation, the most accurate of the common formulas for the general population:

Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

Then that resting figure is multiplied by a factor for how much you train:

Height goes in as centimetres or inches, weight as kilograms or pounds, and the tool converts before it calculates. One note on that last row: the professional athlete setting at 2.4 is genuinely for people whose job is training, several hours a day, most days. It is not for someone who trains hard as a hobby. Picking it when it does not apply will hand you several hundred calories that your body has no intention of burning.

A worked example

Take a 40 year old man, 175 cm tall, 80 kg, exercising moderately 2 to 3 times a week. His resting burn first:

BMR = (10 × 80) + (6.25 × 175) − (5 × 40) + 5
BMR = 800 + 1093.75 − 200 + 5
BMR ≈ 1699 Calories/day

Then the moderate multiplier of 1.6:

Maintenance = 1699 × 1.6 ≈ 2718 Calories/day

So around 2,718 calories a day should keep him where he is. That is today's answer, for today's body, which brings us to the interesting part.

Why your maintenance number moves after you lose weight

If you have recently lost weight, your maintenance calories are almost certainly lower than this calculator says. Not slightly. Meaningfully. And the reason is one of the most uncomfortable findings in obesity research.

Part of it is obvious arithmetic. Lose 10 kg and there is less of you to carry around and keep warm, so your burn falls. The formula already handles that: enter your new weight and you get a new, smaller number.

The other part is not arithmetic, and the formula cannot handle it at all. When you lose weight, your body slows its resting burn by more than the loss of tissue can explain. Scientists call this metabolic adaptation, or adaptive thermogenesis. Your body, in effect, notices what you are doing and quietly turns the thermostat down to resist it.

How much? The clearest evidence comes from a study that followed contestants from the television show "The Biggest Loser", who lost enormous amounts of weight very quickly under extreme conditions. Six years after the competition, most of the weight had come back. Their resting metabolic rate had not. It was still running about 700 calories a day below where they started, and even after accounting for their body composition and age, roughly 500 calories a day of that slowdown could not be explained by their body size at all. It was pure adaptation, and six years on, it had not gone away.

That is an extreme case, so do not read your own future into it. Those were rapid, massive losses under television conditions, not a sensible diet. But the direction of travel is real and it applies broadly, which is exactly why the tool itself tells you that the body adapts to long-term energy restriction. If you have dieted down to your current weight, expect your true maintenance to sit somewhat below the number on the screen. Treat this figure as the ceiling of a range, watch the scale for a few weeks, and let the real world set the final number.

And if this sounds discouraging, take the practical read instead: it is not that maintaining is impossible, it is that maintaining is an active job rather than a coasting one. Knowing the ground is tilted is what lets you lean into it.

Why this number may not match our other calculators

Run your details through this tool and through our TDEE Calculator and you may get two different answers, even though both claim to tell you what you burn in a day. That is not a bug, and we would rather explain it than let you wonder.

Both tools use the same Mifflin-St Jeor equation for the resting part. They differ in the activity multipliers. This calculator uses its own set, which runs 1.2, 1.4, 1.6, 1.75, 2.0 and 2.4. The TDEE calculator uses the more common set, which runs 1.2, 1.375, 1.55, 1.725 and 1.9. So the man in the example above gets 2,718 here at the moderate setting, and about 2,633 from the TDEE tool at its moderate setting, a gap of roughly 85 calories.

Which is right? Neither, strictly. Both multiplier sets are conventions rather than measurements, and the whole activity step is the roughest part of any daily calorie estimate. An 85 calorie gap between two reasonable conventions is a fair illustration of how much precision this exercise really has. Pick one tool, use it consistently, and judge it by what happens on the scale rather than by which number you prefer.

Where the estimate can be off

Beyond adaptation and the multiplier question, the usual honest limits apply:

• It cannot see your body composition. Same age, height, weight and sex gives the same result whether you are mostly muscle or not, even though muscle burns more at rest.
• Health shifts it. Thyroid conditions, medications, pregnancy, breastfeeding and illness all move real needs beyond what a formula predicts.
• The best test is the scale. Eat at the number for two or three weeks and weigh yourself regularly. If your weight is stable, you have found your maintenance. If it is drifting, adjust by a hundred calories or so and watch again. Your own data beats any equation.

Questions people ask

Is maintenance the same as TDEE?

They are the same idea: the calories that hold your weight steady. The only difference here is which multiplier set the tool applies, which is why the two calculators can disagree slightly.

I lost weight and now I am not maintaining on this number. Why?

Most likely metabolic adaptation, explained above. After weight loss your resting burn tends to sit below what your new body size predicts, so your true maintenance is lower than the formula says. Drop by a hundred or two and watch the scale.

Should I pick the professional athlete setting?

Almost certainly not. It is for people who train for a living, several hours a day. Training hard as a hobby is covered by the hard exercise setting.

How often should I recalculate?

Every few kilograms of weight change, or whenever your training load genuinely shifts. Maintenance follows your body, so it needs revisiting as your body changes.

References

Where the figures come from. The resting equation this tool runs is Mifflin-St Jeor, published in the American Journal of Clinical Nutrition, and the point that it is the most accurate of the common equations comes from a systematic review by the Academy of Nutrition and Dietetics. The account of metabolic adaptation, including the six-year follow-up figures quoted above, comes from Fothergill and colleagues at the US National Institutes of Health.

1. 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. 1990;51(2):241-247. https://doi.org/10.1093/ajcn/51.2.241
2. Fothergill E, Guo J, Howard L, et al. Persistent metabolic adaptation 6 years after "The Biggest Loser" competition. Obesity. 2016;24(8):1612-1619. https://pmc.ncbi.nlm.nih.gov/articles/PMC4989512/
3. Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association. 2005;105(5):775-789. https://doi.org/10.1016/j.jada.2005.02.005