How Many Calories Should You Eat Per Day?
Gaurav Yadav
You’ve probably seen the figures: 2,000 calories a day for women, 2,500 for men. They appear on nutrition labels and in health guidance everywhere, and they’re a reasonable population-level average.
They’re also close to meaningless for any individual person. A 5’2” woman in a desk job and a 6’1” man who works construction do not have needs within a thousand calories of each other. Your number depends on your size, your age, your body composition, how much you move, and what you’re trying to do.
Here’s how that number is actually calculated.
The two components
Your daily calorie requirement — usually called TDEE, total daily energy expenditure — is built from two pieces.
Basal metabolic rate (BMR) is what your body burns doing nothing at all. Heart, lungs, brain, temperature regulation, cell repair. This is the largest single chunk for most people, typically 60–70% of the daily total. Even lying in bed all day, you’d burn this much.
Activity is everything on top: walking to the car, standing at your desk, gym sessions, fidgeting, playing with your kids. Formal exercise is usually a smaller slice of this than people expect. The unstructured movement of an ordinary day — sometimes called NEAT — often matters more.
TDEE is BMR multiplied by an activity factor. That’s the whole model.
Calculating your BMR
The most widely used formula is Mifflin-St Jeor, which has held up better than older equations in validation studies:
Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5 Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
A worked example. A 35-year-old woman, 5’5” (165 cm), 150 lb (68 kg):
(10 × 68) + (6.25 × 165) − (5 × 35) − 161 = 680 + 1,031 − 175 − 161 = 1,375 calories per day
That’s her BMR. It is not what she should eat — it’s the floor before any movement is counted.
Applying the activity multiplier
Multiply BMR by the factor that matches your week honestly:
| Activity level | What it means | Multiplier |
|---|---|---|
| Sedentary | Desk job, little deliberate exercise | 1.2 |
| Lightly active | Light exercise 1–3 days/week | 1.375 |
| Moderately active | Moderate exercise 3–5 days/week | 1.55 |
| Very active | Hard exercise 6–7 days/week | 1.725 |
| Extremely active | Physical job plus daily training | 1.9 |
Our example woman, moderately active: 1,375 × 1.55 = 2,131 calories per day to maintain her current weight.
Notice how much the multiplier swings the result. Sedentary would put her at 1,650; very active at 2,372. That’s a 700-calorie spread from one honest self-assessment, which is why this is the step most people get wrong.
Almost everyone overestimates their activity level. Three gym sessions a week alongside a desk job and a car commute is “lightly active,” not “very active.” The multiplier is meant to describe your entire week, not the two hours you’re proudest of. If your results aren’t matching reality after a few weeks, this is the first place to look.
Adjusting for your goal
Once you have your maintenance number, the adjustments are straightforward.
To lose weight: subtract 500 calories per day for roughly a pound a week. A pound of fat holds about 3,500 calories, so a 500-a-day deficit gets you there over seven days. Our example woman would eat around 1,630.
To gain weight or build muscle: add 250–500 calories per day, paired with resistance training so the surplus goes somewhere useful.
To maintain: eat at your TDEE.
Two limits worth respecting. Don’t go below roughly 1,200 calories a day for women or 1,500 for men without medical supervision — below that it becomes genuinely difficult to hit basic nutrient requirements, and the practice tends to backfire. And larger deficits aren’t proportionally better; they mostly increase the odds you abandon the whole thing by week three.
You can run all of this on your own numbers with our Calorie / TDEE Calculator, which handles the arithmetic and shows you maintenance, deficit, and surplus targets side by side.
Why the number is an estimate, not a fact
Every calculator on the internet, including ours, gives you a starting point rather than a measurement. Three reasons.
Individual metabolism varies. Two people with identical height, weight, age, and sex can differ by 200–300 calories in actual BMR. Genetics, thyroid function, and hormonal factors all move the number, and no formula sees any of them.
Body composition isn’t in the equation. Muscle burns more at rest than fat does. Mifflin-St Jeor uses total weight only, so a lean muscular person’s true BMR is underestimated and a higher-body-fat person’s is overestimated. If you know your body fat percentage — our Body Fat Calculator will estimate it — the Katch-McArdle formula, which works from lean mass, tends to be more accurate for you.
Your body adapts. Sustained calorie restriction lowers your expenditure. Some of it is simple physics — a lighter body costs less to move — but some is behavioral, as you unconsciously move less when eating less. This is why a deficit that worked for eight weeks often stalls, and why recalculating every 10–15 pounds of change matters.
How to use the number properly
Treat the calculation as a hypothesis, then let two or three weeks of real data correct it.
Eat at your calculated target consistently. Weigh yourself at the same time of day, several times a week, and average the readings rather than reacting to any single one — daily weight swings of two or three pounds from water and food volume are completely normal and tell you nothing.
After a fortnight, look at the trend. Holding steady when you wanted to lose? Cut another 200 and give it another two weeks. Dropping faster than a pound a week? Add some back — very fast loss disproportionately costs you muscle.
The formula gets you into the right neighbourhood. Your own results tell you the address.
This article is general information, not medical or nutritional advice. If you have a health condition, are pregnant, or are planning a significant change to your diet, speak with a doctor or registered dietitian first.