Estimates only, based on the Mifflin-St Jeor equation. Not medical advice. Adults only.
About this tool
This calorie calculator estimates how many calories you burn in a day and how many to eat to maintain, lose or gain weight. It first works out your basal metabolic rate (BMR), the energy your body uses at rest, with the Mifflin-St Jeor equation. It then multiplies that by an activity factor to get maintenance calories. Everything runs in your browser and nothing is stored.
How to use it
Enter your sex, age, height, weight and typical activity level. Pick the activity level that matches an ordinary week, not your best week, since overestimating it is the most common mistake. The result shows maintenance calories plus targets for slow and steady loss or gain. If you want a goal weight and a timeline, use the calorie deficit calculator; for the protein, carb and fat split, use the macro calculator.
The formula behind it
For men, BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5. For women, the last term is -161 instead of +5. Maintenance calories are BMR times an activity factor from 1.2 to 1.9. As an example, a 30-year-old man who is 180 cm and 80 kg has a BMR of 1780 calories, and about 2,759 calories a day at a moderate activity level. A 30-year-old woman who is 165 cm and 65 kg has a BMR of about 1,370 and maintenance of about 1,884 at light activity.
Activity factors used
| Activity level | Multiplier |
|---|---|
| Sedentary (little or no exercise, desk job) | BMR x 1.2 |
| Lightly active (light exercise 1-3 days a week) | BMR x 1.375 |
| Moderately active (moderate exercise 3-5 days a week) | BMR x 1.55 |
| Very active (hard exercise 6-7 days a week) | BMR x 1.725 |
| Extra active (hard training or a physical job) | BMR x 1.9 |
How many calories to lose or gain weight
A rough rule is that about 3,500 calories equals one pound (7,700 per kilogram) of body weight. Eating 250 calories below maintenance is a gentle pace, 500 is the usual upper range for most people, and larger gaps are harder to sustain. Going above maintenance by 250 to 500 calories supports slow weight gain. The rule is an approximation, and results slow down as your weight changes.
Important limits of any calorie calculator
These numbers are estimates. The equation is based on averages, and real needs differ by muscle mass, genetics, medications and health conditions. Use the result as a starting point, track your weight over two to three weeks, and adjust. Do not eat below the minimum shown without medical supervision, and speak to a doctor or registered dietitian before making big changes, especially if you are pregnant, breastfeeding, under 18, or managing a health condition. This tool is for adults.
Things to watch out for
Calorie needs change as weight, age and activity change, so recalculate every few months. The equation is least accurate for very muscular people, very lean people and people with a lot of body fat. Calorie counts on food labels can be off by 10% or more, so treat any plan as a starting point.
Frequently asked questions
It depends on your size, age, sex and activity. Many adults need roughly 1,600 to 3,000 calories a day to maintain weight. Enter your details above for a personal estimate.
It gives a reasonable starting estimate, usually within about 10% for most people, but it cannot account for individual differences. Track your weight for a few weeks and adjust.
BMR (basal metabolic rate) is the number of calories your body burns at complete rest to keep you alive. Your total daily burn is BMR plus movement and exercise.