Calorie Calculator

Enter your age, sex, height, weight, activity level, and goal to get a daily calorie target, plus the full menu of options from a 2 lb weekly loss to a lean gain, with the math shown step by step.

US units (ft, lbs) Metric (cm, kg)

Male Female

Age (years)

Height (feet)

Height (inches)

Weight (lbs)

Activity level be honest: most people pick one level too high

Goal you get the full menu of options either way

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How this calorie calculator works

This page answers the question people actually type into a search bar: how many calories should I eat? Our TDEE calculator answers a different question (how much do you burn?) and our BMR calculator answers a third (what does your body burn at complete rest?). This one takes that same engine and drives it all the way to a target on your plate.

The pipeline has three steps. First it estimates your BMR with the Mifflin-St Jeor equation, the one most dietitians use. Then it multiplies by an activity factor to get your maintenance calories, the intake at which your weight holds steady. Finally it adjusts maintenance up or down for your goal, using the standard 3,500 kcal per pound convention. You get your target as the headline, and every other goal in a table underneath, because seeing that "2 lb a week" and "0.5 lb a week" are only 750 calories apart is often the most useful part of the answer.

The formula

Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5

Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

Maintenance = BMR × activity factor (1.2 to 1.9)

Daily target = maintenance − (3,500 × lb to lose per week ÷ 7)

Weight is in kilograms and height in centimeters (US units are converted for you). The activity factor runs from 1.2 (sedentary) to 1.9 (hard daily training or physical work). The last line is the goal adjustment: a pound of body fat stores roughly 3,500 kcal, so losing 1 lb a week means eating about 500 fewer calories each day, and gaining works the same way in reverse. That 3,500 figure is a convention, not a law of physics: it dates to a 1958 estimate, and over months it drifts because early loss includes water, metabolism adapts, and a lighter body burns less. It remains the right planning number for the first several weeks, which is exactly how long you should trust any single target before checking it against the scale.

Worked example

A 35-year-old woman, 5 ft 6 in (167.64 cm), 160 lb (72.57 kg), moderately active, aiming to lose 1 lb a week:

BMR = 10 × 72.57 + 6.25 × 167.64 − 5 × 35 − 161 = 1,437 kcal/day

Maintenance = 1,437 × 1.55 = 2,228 kcal/day

Goal adjustment: 3,500 × 1 ÷ 7 = 500 kcal/day, so her target is 2,228 − 500 = 1,728 kcal/day.

Her full menu: 1,978 for a gentler 0.5 lb a week, 1,228 for an aggressive 2 lb a week (right at the edge of the 1,200 floor), 2,478 to lean-gain 0.5 lb a week. Figures are rounded for display; the calculator keeps full precision.

Treat the number as a hypothesis, not a verdict

Mifflin-St Jeor is the best general-purpose equation available without a metabolic lab, and it still only predicts real resting burn within about ±10% for most people. On a 2,200-calorie maintenance, that is a 220-calorie error bar, nearly half a "lose 1 lb a week" deficit, in either direction. So run the experiment: eat your target consistently for two full weeks, weigh in daily, and compare weekly averages (daily weights swing with water and salt; averages tell the truth). Losing faster than planned? Add 100 to 200 calories. Not moving? Subtract the same. Two adjustments in, you know your real number better than any formula does.

The double-counting trap

Here is the mistake that quietly erases the most deficits: picking "moderate" or "very active" because you train, and then also eating back the 400 calories your watch awarded you for this morning's run. The activity multiplier already includes that run. Counting it again means the same workout got you fed twice, and since wrist trackers overestimate exercise burn by 20 to 40% to begin with, the second helping was oversized too. Pick one accounting method: either an activity level that covers your training and no eat-backs, or a sedentary baseline plus conservative add-backs. The first is simpler, and simpler is what survives a busy week.

Maintenance is a moving target

The target you get today has a shelf life. As you lose weight there is less of you to power, so maintenance falls, and your body helps it along by quietly downshifting (less fidgeting, a touch less thyroid output, a phenomenon called adaptive thermogenesis). The practical consequence: the deficit that produced 1 lb a week in January produces half that by April, at the same intake. This is arithmetic, not failure. Re-run this calculator every 10 to 15 lb and let the target walk down with you. And if your pace ever worries you in the other direction, our weight loss rate calculator compares it against published clinical guidelines.

Why we draw a floor at 1,200 and 1,500

If your chosen goal lands below roughly 1,200 calories a day for a woman or 1,500 for a man, this calculator will show the number, and it will also tell you plainly that we do not think you should run it. Below those levels it gets genuinely hard to cover protein, vitamins, and minerals from ordinary food, the deficit is usually steep enough to burn muscle alongside fat, and adherence collapses for all but the most determined. Very low calorie diets exist in medicine, but they are run with supervision, protein targets, and bloodwork. A slower rate loses the same weight with more of it coming from fat; the only thing you give up is the date on the calendar.

Calories are not the whole story, but they are the accounting identity

Protein keeps you full and keeps your muscle; food quality moves your energy, your training, and how much you want to eat tomorrow; sleep and stress lean on all of it. None of that repeals the ledger: weight change over time tracks energy in minus energy out, and every diet that works, works through that identity, whatever its branding says. So use this page for the accounting and our macro calculator to decide what the calories are made of. The order matters: the calorie target sets whether your weight moves, and the macros set how it feels while it does.

Sources

Where the numbers on this page come from. We go to the body that publishes the figure, not to another calculator. See how we verify.

A new predictive equation for resting energy expenditure in healthy individuals (Mifflin and St Jeor, 1990), American Journal of Clinical Nutrition, via PubMed. The BMR equation this calculator is built on.
Body Weight Planner, National Institute of Diabetes and Digestive and Kidney Diseases. NIH's dynamic model of weight change, and the reason we call the 3,500-calorie rule a convention rather than a law.

Frequently asked questions

How many calories should I eat a day to lose weight?

Start from your maintenance calories (what you burn in a typical day) and subtract 250 to 500 for a loss of roughly 0.5 to 1 lb a week. This calculator does that math from your age, sex, height, weight, and activity level. Steeper deficits move the scale faster but cost more muscle and are harder to sustain, and below roughly 1,200 calories a day for women or 1,500 for men it becomes hard to cover basic nutrition from ordinary food.

Is eating 1,200 calories a day safe?

For some smaller, less active women, 1,200 is a workable if strict target. For most people it is below the level where protein, vitamin, and mineral needs are reliably met from food alone, which is why this calculator flags any target under about 1,200 for women or 1,500 for men. Very low calorie diets do exist in medicine, but they run under clinical supervision with monitoring, which a web page cannot provide.

Is the 3,500 calories per pound rule accurate?

It is a useful convention, not a law of physics. A pound of body fat stores roughly 3,500 kcal, so a 500 kcal daily deficit predicts about 1 lb of loss per week, and over a few weeks that prediction is usually in the right neighborhood. Over months it drifts: early loss includes water, your body adapts by burning a little less, and a lighter body has lower maintenance. Treat it as a planning number and re-run the calculator as your weight changes.

Should I eat back the calories my watch says I burned exercising?

Not if you picked an activity level that already includes your training, which is what the activity multiplier is for. Adding tracker calories on top counts the same workout twice, and wrist trackers routinely overestimate exercise burn by 20 to 40% on top of that. If you want exercise to earn extra food, set your activity level to sedentary and add back a conservative estimate; picking one method and sticking to it is the whole game.

Why am I not losing weight on my calculated calories?

Three usual suspects, in order of likelihood: the estimate is off for your body (any BMR equation is only accurate to about plus or minus 10%), the logging is off (untracked oils, bites, and weekends add up faster than people expect), or your activity level is set too high. Hold the target steadily for two full weeks, weigh in daily and average the week, and if the trend has not moved, drop the target by 100 to 200 calories and repeat.

What is the difference between this and a TDEE calculator?

Same engine, different question. A TDEE calculator answers "how much do I burn?" and stops at maintenance. This page goes one step further and answers "how much should I eat?" by adjusting maintenance for a specific goal, showing every goal option side by side, and flagging targets that fall below a safe floor. If you just want your burn, our TDEE calculator is the cleaner tool for that.

Do I need to recalculate as I lose weight?

Yes, roughly every 10 to 15 lb. Maintenance calories scale with body size, so the deficit that produced 1 lb a week at your starting weight quietly shrinks as you get lighter. Plateaus a few months in are often just this arithmetic catching up, not a broken metabolism. Re-run the numbers at your new weight and the pace usually resumes.