Calorie Calculator

Estimate how many calories you burn in a day, then see daily targets for keeping, losing or gaining weight at a steady pace.

Units
Sex
Maintenance calories
–
GoalCalories/day

Estimates for healthy adults. Weight change is rarely perfectly steady, so check your progress every few weeks.

How the calorie calculator works

  1. Your resting energy (BMR) is estimated with the Mifflin-St Jeor equation from your sex, age, height and weight.
  2. BMR is multiplied by an activity factor to give your total daily energy expenditure, the calories you burn on a typical day.
  3. Targets for losing or gaining weight are set by subtracting or adding 250 to 1,000 calories a day.
BMR (men) = 10 × kg + 6.25 × cm − 5 × age + 5
BMR (women) = 10 × kg + 6.25 × cm − 5 × age − 161
Maintenance = BMR × activity factor

Worked example

A 35-year-old woman who is 5 ft 5 in (165 cm), weighs 150 lb (68 kg) and exercises lightly has a BMR of about 1,376 calories. Multiplied by 1.375, her maintenance is about 1,891 calories a day. A target of about 1,391 calories would aim for roughly 1 lb of weight loss a week.

Tips for using your number

  • Treat it as a starting estimate. Formulas can be off by 10% or more for an individual.
  • Track for two to three weeks. If your weight isn't moving the way you expect, adjust by 100 to 200 calories.
  • Pick a pace you can keep. Slower changes are usually easier to maintain.
  • Food quality still matters. Protein, fiber, fruit and vegetables help you feel full on fewer calories.

Want to split your calories into protein, carbs and fat? Use the macro calculator. For a goal date, try the calorie deficit calculator. This tool gives general estimates and is not medical advice.

Last reviewed October 2026.

Frequently asked questions

How many calories should I eat a day?

It depends on your size, age, sex and how active you are. This calculator estimates the calories you burn each day (your maintenance level) and shows targets above and below it for gaining or losing weight. Use the numbers as a starting point and adjust after a few weeks based on how your weight actually changes.

How is the number worked out?

It uses the Mifflin-St Jeor equation to estimate the calories you burn at rest, then multiplies that by an activity factor between 1.2 (little exercise) and 1.9 (hard daily training). The result is your estimated maintenance calories.

Why does 500 calories a day mean about 1 lb a week?

A pound of body fat is often estimated at around 3,500 calories, so a daily gap of 500 calories adds up to about 3,500 a week. It is a rough rule: real weight change usually slows over time as your body adapts.

Why are some targets marked as low?

Many guides suggest that adults should not go below about 1,200 calories a day (women) or 1,500 (men) without supervision from a doctor or dietitian. When a target falls below that, the calculator flags it.

Is this calculator suitable for everyone?

It is designed for healthy adults. It is not suitable for children, pregnant or breastfeeding people, or anyone with a medical condition. It is a general estimate, not medical or nutrition advice.