Calorie Calculator

If you're wondering "how many calories should I eat per day?" — the honest answer depends on your body and your goal, but this calculator gives you a solid, personalized starting number in under a minute. Enter your age, height, weight, and how active you are, plus whether you want to lose weight, gain weight, or stay where you are, and you'll get a daily calorie range to aim for.

We estimate your BMR — the calories your body burns just staying alive at rest — using the Mifflin-St Jeor equation, the formula considered most accurate for healthy adults. We then multiply that by how active you are day-to-day to get your full daily calorie burn, and shift it up or down based on whether you want to lose, maintain, or gain weight.

This number goes by a more technical name in fitness and nutrition science: TDEE, or Total Daily Energy Expenditure. If you're already familiar with that term, want to see BMR and TDEE broken out separately instead of just the final range, or want a fuller explanation of what each activity level actually means, check out our TDEE Calculator.

A calorie deficit just means eating fewer calories than your body burns in a day — when that happens, your body makes up the difference by using stored energy (body fat), which is the basic mechanism behind weight loss. A calorie surplus is the opposite: eating more than you burn, which supports weight gain over time. Eating roughly the same number of calories you burn — your maintenance level — keeps your weight fairly stable. The range the calculator gives you above is already built around whichever one of these fits your goal, so you don't need to calculate it yourself.

There's no single number that works for everyone — that's why this calculator asks for your details instead of giving a flat answer. As a rough reference point, one pound of body weight is often estimated at around 3,500 calories, a figure that traces back to research from the 1950s.

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More recent research has shown this is a useful approximation rather than an exact rule — your body adjusts somewhat as you lose weight, so results aren't perfectly linear week to week.

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In practice, this means a moderate, steady calorie deficit is generally easier to sustain and easier to predict than a very aggressive one, which is part of why the ranges above avoid extreme numbers by default.

A few things that trip up a lot of people the first time they use a number like this:

Your activity level is easy to overestimate. Most people round up when guessing how active they really are day to day, which pushes the calorie number higher than it should be. If your results don't seem to be lining up with your weight over a few weeks, it's worth re-checking that input first.

Weight loss isn't perfectly steady. Water retention, hormones, sleep, and sodium intake can all move the scale by a pound or two in either direction on any given day, even when you're doing everything "right." Look at the trend over a couple of weeks rather than judging by any single day.

The number isn't meant to be permanent. As you lose or gain weight, the calories your body needs change too, so it's normal — and expected — to recalculate every so often rather than treating one result as fixed forever.