Calorie Calculator
Daily calories to maintain, lose or gain weight, from your size and activity.
How to use Calorie Calculator
- Choose your units and enter sex, age, weight and height.
- Pick the activity level that matches a normal week, and a goal.
- Read your daily calorie target and the table of other goals.
How it works
First your basal metabolic rate (BMR), the energy your body uses at complete rest, is estimated with the Mifflin–St Jeor equation (1990): men 10 × kg + 6.25 × cm − 5 × age + 5; women the same with −161 instead of +5. Reviews by the Academy of Nutrition and Dietetics found it the most accurate of the common equations for adults. If you enter your body-fat percentage, the Katch–McArdle equation (370 + 21.6 × lean mass in kg) is used instead.
BMR is multiplied by an activity factor (1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active) to estimate maintenance calories, often called TDEE. For a weight goal, a daily amount is added or removed using the planning figure of 7,700 kcal per kilogram of body weight (about 3,500 kcal per pound): 0.5 kg a week is 550 kcal a day.
The tool warns when a target falls below 1,200 kcal a day for women or 1,500 for men, levels that are generally not advised without medical supervision.
Example
A 30-year-old man, 80 kg and 180 cm: BMR = 800 + 1,125 − 150 + 5 = 1,780 kcal. Moderately active: 1,780 × 1.55 = 2,759 kcal to maintain. To lose 0.5 kg a week: 2,759 − 550 = 2,209 kcal a day.
Frequently asked questions
How many calories should I eat to lose weight?
Fewer than you use. A deficit of about 500 kcal a day gives roughly 0.5 kg (1 lb) a week for most people. Enter your details and choose a goal to see your number.
How accurate is this?
Equations like Mifflin–St Jeor are within about 10% of measured resting energy for most adults, and the activity factor adds more uncertainty. Treat the result as a starting point and adjust after two or three weeks of real results.
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest. TDEE (total daily energy expenditure) adds movement and exercise: it is BMR × your activity factor, shown here as "To maintain weight".
Is a 1,200-calorie diet safe?
Very low intakes make it hard to get enough nutrients and can be unsafe for some people. Health bodies generally advise against going below about 1,200 kcal (women) or 1,500 kcal (men) without medical supervision.
Does weight loss follow the 7,700 kcal per kg rule exactly?
No. It is a planning average. Real loss slows as your body weight and energy needs fall, and water changes hide progress week to week.
Limitations
- Adults aged 15–100; not for children, pregnancy or breastfeeding.
- Very muscular or very lean people are estimated better with the body-fat option.
- Activity factors are broad categories, not measurements.
- An estimate for healthy adults, not medical advice. Talk to a doctor or registered dietitian about your own situation.
Last reviewed November 9, 2026. How we build and test tools.