What "maintenance" actually means
Maintenance calories are the amount of food energy that leaves your weight roughly where it is, not a single number engraved to the calorie. Every input behind the figure above carries its own error: a bathroom scale reading, a self-reported activity level, a formula built from population averages rather than your personal metabolism. Put those together and the honest result is a band, not a point, typically about 150 kcal wide on either side of the number this page gives you.
Formula error does most of the work here. Even the best-performing equations land within roughly 10 percent of a lab-measured value for most adults, which alone is enough to shift the honest range by 150 to 200 kcal at typical maintenance levels. Add a slightly generous activity guess and the range only widens further.
That is worth sitting with, because most people treat maintenance like a knife-edge and panic the moment the scale moves. It is not one. A day 150 kcal over your number, or under it, sits inside ordinary measurement noise and normal day-to-day shifts in water, sodium and gut contents, none of it fat gained or lost overnight. Treat the figure above as the centre of a comfortable range you can live inside, not a line that punishes you for crossing it.
The weekly-budget mindset
A daily target is a planning convenience, not a biological deadline. Your body settles its energy accounts over roughly a week rather than between one midnight and the next, so the more useful question is not "did today land on the number" but "did this week average out close to it".
The table further up spells out three ways to spend an identical weekly total. Flat eats the same amount every day, which suits anyone who finds a fixed routine easier to hold than a variable one. Weekend loose trims a couple of hundred calories from Monday to Friday and banks them for two bigger days, suited to a social life built around Friday and Saturday nights. The 5:2-style pattern goes further still: five ordinary days a little over maintenance and two noticeably lighter days, useful if you would rather take fewer, bigger gaps than seven small ones. None of the three patterns is more correct than the others, because the weekly total, the number that actually decides your weight, is identical across all of them.
Bend the week however suits you. What matters is that the bending still lands on the same total, which is exactly what drift, covered next, quietly breaks without anyone deciding to break it.
Drift, the silent kilogram
A hundred extra calories a day sounds too small to matter, which is exactly why the arithmetic is worth doing once. At roughly 7,700 kcal per kilogram of body fat, a steady 100 kcal daily surplus adds up to about 36,500 kcal across a year, close to 4.7 kg. That is a splash more oil in the pan, a slightly generous glass of wine, or one biscuit, repeated for twelve months without anyone ever deciding to gain weight on purpose.
The drift table above runs the same sum for six common gaps, from a gentle 100 kcal to a serious 500, in both directions. The reverse holds just as firmly: a quiet 250 kcal shortfall most days, the kind that creeps in during a busy month or a spell of low appetite, drains close to 12 kg across a year without anybody calling it a diet.
The difference between a bent week and real drift is intent. The patterns in the section above return to the same weekly total on purpose. Drift is the gap nobody chose and nobody is tracking, and it never announces itself in the moment. It shows up months later, as clothes that fit differently and no obvious culprit to blame.
The same arithmetic runs the other way for anyone building muscle on purpose. A deliberate 250 kcal surplus most days is a sensible, patient bulk; the identical gap arriving by accident, on top of a number you thought was maintenance, is just weight gain with better branding. The drift table does not know which one you meant. Only you do.
Getting back to maintenance after a diet
Coming off a diet is where most maintenance mistakes happen, and almost none of them are about willpower. Weeks spent under maintenance leave actual energy expenditure running a little below what the equation predicts, hunger signals turned up, and glycogen stores in muscle and liver run down. Jump straight to the full maintenance number in one move and two things happen together: your true burn is still catching up, and every gram of glycogen you refill pulls roughly three grams of water in with it.
Both effects show up on the scale in the first one to two weeks back at maintenance, typically 1 to 2 kg, and almost none of it is fat. It is restored fuel and the water that travels with it, and it settles once those stores are topped back up. Cutting calories again to chase that number back down just restarts the diet and delays the metabolic recovery the extra food was meant to deliver.
A steadier route back adds calories in stages: roughly 100 to 150 kcal every one to two weeks rather than the full jump at once. It gives appetite and expenditure time to catch up with each other, and it makes the early water-weight bump easier to read for what it is instead of mistaking it for the diet reversing itself. Weigh in daily through this stretch and watch the seven-day average rather than any single morning; the average climbs gently and levels off, where single readings just look alarming. Anyone coming off a longer or more aggressive cut, the kind planned with the Calorie Deficit Calculator, tends to need this step-up the most.
When to recalculate
Recalculate whenever the inputs genuinely move: after roughly 4 to 5 kg of weight change in either direction, after a job that changes how much of the day you spend on your feet, after starting or stopping regular training, and again three to six months after finishing a diet once your weight has held steady for a few weeks. Pregnancy, a new medication or a diagnosed thyroid condition also warrant a fresh number and, more usefully, a conversation with a doctor rather than a formula. The equation is only as good as what goes into it, and a stale number is the most common reason a "maintenance" target quietly stops holding. Updating it takes ten seconds: new weight, new activity level, done.
Questions people ask
Do I need to eat maintenance calories on rest days too?
Broadly, yes. Maintenance is already an average across your whole week, training days and rest days included, so there is no separate "rest day number" hiding underneath it. Some people naturally eat a little less on quiet days simply because appetite drops without training, which is fine, but it is a preference, not something the arithmetic requires.
Why am I gaining weight at what I calculated as maintenance?
Usually one of two things. Portions have quietly grown, sauces, oils and drinks are the easiest things to undercount, and they close the gap between real intake and the calculated number faster than anyone notices. Or the activity level selected overstates a normal week; picking "moderately active" for two gym sessions bookended by a desk job is a common mistake. Watch your weight trend over two to three weeks before changing anything, and if it is genuinely climbing rather than just bouncing, trim the number by 100 to 150 kcal.
How long after a diet does maintenance start to feel normal?
Most people find hunger and energy level out within two to six weeks of eating consistently at maintenance, though a longer or more aggressive diet can stretch that further. Judge it by the trend rather than any single week: once your weight has held roughly steady for three or four weeks running, you have arrived, whatever the scale did in week one.
Is maintenance the same thing as TDEE?
Yes. Total daily energy expenditure (TDEE) is what your body spends in a day; maintenance calories are what you eat to match that spend exactly. They are the same number seen from two directions, spending and eating. If you are still narrowing down what that number should be, the Daily Calorie Calculator walks through the same formulas with more detail on choosing an activity level.
Should I track my food forever to stay at maintenance?
No. Tracking earns its keep while you are calibrating: learning your real portions, checking a new number after a diet, or working out why the scale has started drifting. Once you have a feel for what your maintenance amount looks like on a plate, most people can step back to loose tracking or none at all, and simply weigh in occasionally to catch drift early. Treat the scale as the long-term check and food logging as the tool you pick back up if it disagrees with you.
This tool estimates energy needs for healthy adults and is not medical advice. Pregnancy, breastfeeding, a history of disordered eating, thyroid conditions and some medications change the arithmetic enough that a clinician's input matters more than another decimal place of precision here.