Calorie Calculator

Enter your age, sex, height, weight and activity level to estimate how many calories your body uses each day, and what that means for losing, keeping or gaining weight. Your numbers stay in your browser.

Age

years

For adults 18 and over

Height

Weight

Activity level

SedentaryLittle or no exercise, desk jobLightly activeLight exercise 1 to 3 days a weekModerately activeExercise 3 to 5 days a weekVery activeHard exercise 6 to 7 days a weekExtra activeVery hard exercise or a physical job

Calories to keep your weight the same

1,961 kcal / day

Your body uses about 1,427 calories a day at rest (BMR). With your activity level that comes to about 1,961.

Calories for your goal

Lose about 0.5 kg (1 lb) a week1,461 kcal
Lose about 0.25 kg (½ lb) a week1,711 kcal
Maintain weight1,961 kcal
Gain about 0.25 kg (½ lb) a week2,211 kcal
Gain about 0.5 kg (1 lb) a week2,461 kcal

Eating under about 1,200 calories a day without medical supervision is not usually recommended. Weight changes more slowly than these numbers suggest, and rapid loss can be harmful.

A balanced split at 1,961 kcal

Protein (30%): 147 g
Carbohydrates (40%): 196 g
Fat (30%): 65 g

The split is just one common example. Your needs depend on your health, goals and what your doctor or dietitian advises.

How your calorie needs are worked out

Your body burns calories even at rest, to breathe, pump blood and keep warm. This is your basal metabolic rate (BMR). The calculator estimates it with the Mifflin-St Jeor equation: 10 × weight in kg + 6.25 × height in cm − 5 × age, then +5 for men or −161 for women. It then multiplies by an activity factor to include the calories you burn moving around.

Activity levels

Level	What it means	Multiplier
Sedentary	Little or no exercise, desk job	1.2
Lightly active	Light exercise 1 to 3 days a week	1.375
Moderately active	Exercise 3 to 5 days a week	1.55
Very active	Hard exercise 6 to 7 days a week	1.725
Extra active	Very hard exercise or a physical job	1.9

Losing or gaining weight

A common rule of thumb is that about 3,500 calories (7,700 per kg) equal a pound (kg) of body fat, so 500 fewer calories a day tends to lose about 0.5 kg (1 lb) a week.
Real weight change is not perfectly steady: water, muscle and your metabolism all change as you lose or gain.
Gradual change is usually safer. Eating below about 1,200 calories (women) or 1,500 (men) a day is not usually recommended without medical supervision.
Choose a plan you can keep, with enough protein, fibre and a variety of foods.

About the macro split

The example split of 30% protein, 40% carbohydrates and 30% fat is one common pattern, shown in grams using 4 calories per gram of protein and carbohydrate and 9 per gram of fat. Health bodies suggest wide ranges for each, and the best mix depends on your health and goals.

Who this is not for

Children and teenagers, who are still growing.
Pregnant or breastfeeding women, who need extra energy and nutrients.
People with diabetes, thyroid, heart or kidney disease, or an eating disorder.
Anyone on a medically supervised diet. Follow your care team's advice instead.

How to use the Calorie Calculator tool

Choose your sex and units, then type your age, height and weight.
Pick the activity level that best matches a normal week.
Read the calories you need to keep your weight, and the targets for losing or gaining slowly.
Look at the example split of protein, carbohydrates and fat for those calories.

Frequently asked questions

How many calories do I need a day?

It depends on your age, sex, size and activity. This calculator estimates your resting calories with the Mifflin-St Jeor equation and multiplies by an activity factor to give the calories that keep your weight steady.

What is BMR?

Basal metabolic rate (BMR) is the energy your body uses at rest to breathe, circulate blood and keep warm. Your daily calories are your BMR multiplied by an activity factor from 1.2 for a desk job to 1.9 for very hard exercise.

How many calories should I cut to lose weight?

A common guide is 250 to 500 calories a day below maintenance, which tends to lose about 0.25 to 0.5 kg (½ to 1 lb) a week. Slow, steady loss is usually safer than crash diets, and you should not go below about 1,200 calories (women) or 1,500 (men) without medical supervision.

How accurate is this?

It is an estimate. Real calorie needs can differ by several hundred calories because of muscle mass, genes, hormones, medicines and daily movement. Watch your actual weight over a few weeks and adjust.

Is this suitable for children, teenagers or pregnancy?

No. The formula is for healthy adults. Children, teenagers, pregnant or breastfeeding women and people with medical conditions have different needs and should get advice from a health professional.