How many calories do you need a day?
Five questions, one number. This tells you what you burn on an average day, and what to eat to lose, gain or hold your weight — with the formula on the page rather than hidden behind it.
How the number is worked out
Your body burns calories in two places: keeping you alive, and moving you around. The first is your basal metabolic rate, and it is the larger share for almost everybody — a sedentary office worker spends roughly two-thirds of their daily energy simply existing.
Women: (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Maintenance = BMR × activity factor
The activity factor runs from 1.2 for someone who sits all day to 1.9 for a manual worker training twice a day. This is where most calculators go wrong for most people, because almost everyone picks a level up from where they really are. Three gym sessions a week around a desk job is lightly active, not very active.
Turning a calorie target into weight change
A kilogram of body fat holds roughly 7,700 kcal. Divide that across a week and a 550 kcal daily deficit is about half a kilo — which is the rate most people can actually keep to without their training, sleep or mood falling apart.
Two things that surprise people. First, the deficit shrinks as you do: a lighter body burns less, so the target that worked in month one stalls in month four. Second, the scale moves for reasons that have nothing to do with fat — salt, carbohydrate, sleep and, for women, cycle phase can swing weight by two kilos inside a week. Judge a calorie target on a four-week trend line, never on a single morning.
Questions people ask
How many calories should I eat to lose weight?
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Take your maintenance figure and subtract. A deficit of about 550 kcal a day works out at roughly half a kilo a week, which is a rate most people can hold. Anything faster is harder to sustain and costs you more muscle. The table on this page does that arithmetic for you at four different rates, and refuses to go below a safe minimum.
Which equation does this use?
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Mifflin-St Jeor, published in the American Journal of Clinical Nutrition in 1990. It is more accurate in modern populations than the older Harris-Benedict equation and is what ACSM and dietetic guidance recommend. Your resting metabolism is multiplied by an activity factor to reach maintenance.
Why won't it give me a lower number?
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Two safety floors apply. Your target never drops below your resting metabolism, and never below 1,500 kcal for men or 1,200 for women. Below those intakes you cannot assume you are getting enough micronutrients without supervision. Where a floor binds, we say so on the page rather than quietly changing the number.
How accurate is it?
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The equation predicts resting metabolism to within about 10% for most people, and the activity multiplier is a bigger source of error than the equation itself — most people overestimate how active they are. Treat the number as a starting point. Eat at it for two weeks, track your weight, and adjust by 100–200 kcal based on what actually happened.
Do I need to count calories forever?
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No. Most people count for a few weeks to learn what portions actually look like, then stop and keep the habits. Counting is a measuring tool, not a lifestyle.
Related calculators
A number is a starting point, not a plan.
This calculator can tell you where you are. It cannot watch your form, adjust when your knee flares up, or keep you consistent in week six. If you want that part, we run a private studio in Kharadi and the first session is free.
This tool provides general fitness and nutrition information for healthy adults aged 18 and over. It is not medical advice, diagnosis or treatment. Speak to a doctor before starting any new exercise or nutrition programme, particularly if you have a health condition, are pregnant or post-partum, or have a history of disordered eating.