Calorie calculator

How many calories you burn in a day, at rest and with your activity: roughly what keeps your weight steady.

Calories you burn a day

2,084 calories

moderately active, at 143 lb

1,345 at rest
Activity × 1.55

At 35, 5 ft 5 in and 143 lb, a moderately active woman burns about 2,084 calories a day: roughly what you can eat to keep your weight where it is.

About 1,345 of them keep your body running at rest; moving around and exercise add the other 739.

I’m not a doctor or a dietitian. This is an estimate, for information only. For decisions about your health, check with a professional.

Your numbers

example: change the numbers

Units

The math stays the same. Only the way the numbers are shown changes.

Metrickg · cmUSlb · ftUKst · ft

Sex

The formula has one version for men and one for women.

FemaleMale

Age

For adults: the formula was built on people aged 19 to 78.

Height

Weight

Your weight today.

How active you are

Think of a typical week, including your job.

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Your calories at each activity level
Activity level	Multiplier	Calories a day
Sedentary	× 1.2	1,613
Lightly active	× 1.375	1,849
Moderately active (you)	× 1.55	2,084
Very active	× 1.725	2,319
Extra active	× 1.9	2,555

How it works

First, your resting burn: the calories your body uses in a day at complete rest. The calculator uses the Mifflin-St Jeor equation (1990): 10 × weight in kilograms + 6.25 × height in centimeters − 5 × age, then + 5 for men or − 161 for women. Pounds, feet and inches are converted first.
Then it multiplies by an activity factor: 1.2 if you’re sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extra active. The result is what you burn on a typical day, which is roughly what you can eat to keep your weight steady.
These are food calories, the ones on nutrition labels (kilocalories, or kcal).

Worked example

A 35-year-old woman, 5 ft 5 in (165.1 cm) and 143 lb (64.86 kg): 10 × 64.864 + 6.25 × 165.1 − 5 × 35 − 161 = 1,344.5 calories at rest. Moderately active, × 1.55 = 2,084 calories a day. If she were sedentary, she would burn about 1,613; if very active, about 2,319.

Sources

Text checked on September 30, 2026

Good to know

It’s an estimate. In a 2005 review, this equation came within 10% of the measured value for more people than any other common equation, but for some people it misses by more.
The activity multipliers are a convention: nearly every calculator uses these five, but nobody measured them for you. If your weight keeps drifting while you eat this amount, your real number is a bit different.
Older adults and some ethnic groups were underrepresented in the studies behind these equations, so the estimate is less certain for them.
It isn’t meant for pregnancy, breastfeeding, teens or athletes in heavy training: their needs are different, and a doctor or registered dietitian can work them out.

Frequently asked questions

How many calories do I need a day?

It depends on your age, sex, height, weight and how active you are, which is what this calculator works out. As a rough guide, the NHS says an average man needs about 2,500 calories a day and an average woman about 2,000. US nutrition labels use 2,000 a day for general advice.

What’s the difference between BMR and TDEE?

BMR (basal metabolic rate) is what you burn at complete rest; this calculator gives your resting burn, which is very close to it. TDEE (total daily energy expenditure) adds everything you do in a day. The small number above is your resting burn, the big one your TDEE.

How many calories should I eat to lose weight?

US obesity guidelines often start with 500 to 750 fewer calories a day than you burn. The calorie deficit calculator works out your number and how many weeks it takes to reach a goal, with the safety limits.

Why do other calculators give a different number?

They use different equations and different activity multipliers. The older Harris-Benedict equation, for example, came out about 5% above measured values in the 1990 study that produced the Mifflin-St Jeor equation used here.

Does it work for teenagers?

No, it’s for adults. The equation was built on people aged 19 to 78, and teens need extra energy to grow, as the Dietary Guidelines for Americans point out. A pediatrician or registered dietitian can help.