Last reviewed on 11 September 2026.
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This page explains the parts that make up maintenance, why calculators disagree, and how to find your own number from your intake and your weight. It does not calculate anything itself. For a starting estimate, use the TDEE calculator, then read on to see what that number does and does not mean.
What are maintenance calories?
Maintenance calories are the kilocalories you need to eat each day, on average, for your weight to stay the same. At maintenance, energy in and energy out balance over days and weeks, not meal by meal. The figure is the same thing as total daily energy expenditure, usually shortened to TDEE. It is not fixed: it moves with your weight, activity, muscle mass, age and health. A calculator hands you one number, but your real maintenance is better thought of as a band a hundred or two kilocalories wide, which shifts a little from week to week.
What is basal metabolic rate, and how much of maintenance is it?
Basal metabolic rate, or BMR, is the energy your body uses at complete rest to run the heart, brain, liver, kidneys, breathing and body temperature. In most adults it makes up roughly 60 to 70 per cent of the daily total, and an even larger share in people who move very little. It depends mainly on body size and especially on fat-free mass, which is why men, taller people and more muscular people tend to have higher figures. The BMR calculator estimates this resting figure on its own. It describes a body lying still all day, so it is never an eating target.
| Part of the total | Share of the day | What it covers |
|---|---|---|
| Basal metabolic rate | About 60 to 70 per cent | Heart, brain, liver, kidneys, breathing and body temperature at rest |
| Thermic effect of food | About 10 per cent | Digesting, absorbing and storing what you have eaten |
| Activity, including NEAT | Under 20 per cent for a desk worker, 30 per cent or more for physical work | Deliberate exercise plus all the movement nobody calls a workout |
The last row is the part that varies most between two people of the same size, and the part a calculator can only guess at.
What is the thermic effect of food?
It is the energy spent digesting, absorbing and storing what you eat, and it accounts for about 10 per cent of daily expenditure on a mixed diet. Protein costs the most to process, roughly 20 to 30 per cent of its own calories, carbohydrate around 5 to 10 per cent, and fat very little. This is one reason a higher-protein diet can feel slightly easier while losing weight, but the effect is small in absolute terms. Changing the mix of foods on your plate shifts the thermic effect by tens of kilocalories a day, not hundreds.
What is NEAT, and why does it matter for maintenance?
NEAT, or non-exercise activity thermogenesis, is the energy you spend on movement that is not deliberate exercise, and it is the main reason activity is the most variable part of maintenance. Activity may be under 20 per cent of the total for a desk worker who does no exercise, and 30 per cent or more for someone doing physical work or training daily. An hour at the gym burns a few hundred kilocalories, but a day on your feet in a shop, a kitchen or a hospital ward can burn more than that without anyone calling it a workout. NEAT also tends to fall quietly when people diet, as they sit more and move less without noticing. That drop is one reason weight loss slows even when food intake has not changed at all.
Why do maintenance calorie calculators give different answers?
They start from different equations, ask different questions and multiply by different activity factors. One calculator may use Mifflin-St Jeor, another the older Harris-Benedict equation, and a third may ask for your body fat so that it can use Katch-McArdle. Some ask about your job and your exercise separately; others fold both into a single choice from sedentary to very active. A small difference in the resting estimate is then multiplied, so a 70 kcal gap at rest can widen past 100 by the end. None of these tools measures you. Each predicts you from averages.
Which BMR equation is the most accurate?
For healthy adults, Mifflin-St Jeor is generally considered the most reliable of the common equations, and it is the one the NNWA calculators use. Validation studies, mostly in American and European adults, found it predicted measured resting expenditure within about 10 per cent for most people, though not for everyone. Harris-Benedict, first published in 1919 and revised in 1984, tends to give slightly higher figures. Katch-McArdle works from lean body mass instead of weight, which can suit very muscular people, but only when the body fat measurement is reasonably accurate, and home scales often are not.
How much does the activity level you choose change the result?
More than anything else you enter. Take a 30-year-old woman who is 160 cm tall and weighs 60 kg. Mifflin-St Jeor puts her resting rate at about 1,290 kcal. Multiplied by 1.2 for a sedentary day, her maintenance comes out near 1,550 kcal; at 1.375 for light activity, about 1,770; at 1.55 for moderate activity, close to 2,000. That is a spread of about 450 kcal from one drop-down menu. People commonly rate themselves a full band more active than they are, so when in doubt choose the lower level and let your weight trend correct it.
Do South Asians have lower maintenance calories?
Possibly, on average, though the evidence is not settled. Several studies comparing South Asian and white European adults have reported lower resting energy expenditure in South Asians of similar size, partly explained by less lean mass and more body fat at the same weight. Some Indian studies have also found that standard equations overestimate measured resting expenditure in Indian adults. Others find little difference once body composition is taken into account. The practical lesson is modest: if you are South Asian, treat a calculator's figure as a possible overestimate and let your own records settle it.
Does maintenance change as you lose weight or get older?
It changes with weight, and with age less than most people assume. A lighter body needs less energy to run and to move, so every few kilograms lost lowers maintenance, which is why an intake that once produced steady loss eventually only holds weight. Re-estimate after each change of 4 or 5 kg. On age, a large analysis published in Science in 2021 found that energy expenditure adjusted for body size stays fairly stable from about 20 to 60 and declines after that. Lost muscle and lower activity probably explain more of the midlife change than metabolism slowing on its own.
How do you find your real maintenance calories?
By measuring rather than predicting. Eat your normal diet and record everything, including cooking oil, sugar in tea and snacks, for two to three weeks. Weigh yourself each morning after using the toilet and before eating, and work out a weekly average. If that average stays flat, your average daily intake is close to maintenance. If it drifts down by about a quarter of a kilogram a week, your maintenance is roughly 250 to 300 kcal above what you ate; if it drifts up, it is below. The Indian food calorie counter helps with household portions.
Finding your own maintenance by measuring it
Two to three weeks of honest records beats any equation, because every equation is built from averages of other people.
Eat the way you already eat
Do not change the diet for the test. What you want is the intake that produced the weight you are carrying now.
Record everything, including the invisible
Cooking oil, sugar in tea, snacks and weekend meals. Under-recording these is the commonest reason the exercise gives a wrong answer.
Weigh yourself the same way each morning
After the toilet and before eating, every day, and then take a weekly average instead of reading single mornings.
Read the trend rather than the scale
A flat weekly average means your average intake is close to maintenance. A drift down of about a quarter of a kilogram a week puts maintenance roughly 250 to 300 kcal above what you ate.
Re-estimate as your weight moves
A lighter body needs less energy to run and to move, so check again after every 4 or 5 kg, since an intake that once produced loss will eventually only hold.
Why does your weight jump around from day to day?
Mostly water. A salty restaurant meal, a larger helping of carbohydrate, constipation, a hard workout or the days before a period can each move the scale by half a kilogram to a kilogram or more overnight, with no change in body fat. That noise is why a single weigh-in says almost nothing about maintenance. Weekly averages smooth it out, and comparing the same phase of the menstrual cycle from month to month saves women false alarms. Honest logging matters as much: people routinely under-record what they eat, especially oil, snacks and weekend meals.
How do maintenance calories relate to losing or gaining weight?
Maintenance is the reference point everything else is measured from. To lose weight you eat consistently below it, and to gain you eat consistently above it. How far below is a separate question with its own trade-offs, taken up in the calorie deficit, explained properly. How far above, and how quickly weight then comes on, is set out in the weight gain calorie chart. Without a reasonable maintenance figure both plans are guesswork, which is why finding it first, even roughly, saves weeks of confusion later.
The short version
Maintenance calories are what your body burns on a typical day: mostly resting metabolism, a little for digesting food, and a variable amount for movement. Calculators estimate the figure from averages and disagree because of their equations and activity factors. Start with an estimate, then track intake and morning weight for two to three weeks and adjust. The number your own scale confirms is the one to plan around.