Calorie Calculator (BMR and TDEE)
Estimate the calories your body uses in a day, from your age, sex, height, weight and activity level. General information, calculated in your browser.
Estimates
The same person at each activity level
Simple subtraction against the estimate above. It is not a recommendation.
Published formula
Uses the Mifflin-St Jeor equation and standard activity multipliers. The numbers are shown with their working, not hidden.
Honest about accuracy
Results are estimates, with a stated margin. We show every activity level so you can see how much the choice matters.
Private
Your age, weight and height stay in your browser. Nothing is uploaded, stored or tracked.
How the numbers are worked out
The Mifflin-St Jeor equation estimates resting energy use in kilocalories per day:
- Male: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Female: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
For example, a 55-year-old man who is 178 cm and 80 kg has a BMR of 800 + 1,112.5 − 275 + 5 = 1,642.5 kcal. Multiplying by an activity factor of 1.2 to 1.9 gives the estimate of total daily use. See also the BMI calculator, and the unit converter for other measurements.
Frequently Asked Questions
What is BMR?▼
Basal metabolic rate is the energy your body uses just to stay alive at rest: breathing, circulation, keeping warm and running your organs. It is usually the biggest part of the energy you burn in a day. This calculator estimates it with the Mifflin-St Jeor equation, a widely used formula from 1990.
What is TDEE?▼
Total daily energy expenditure is the estimated number of calories you burn in a day, including everything you do. It is your BMR multiplied by an activity factor from 1.2 for little exercise up to 1.9 for very hard training. The result is often called an estimate of 'maintenance' calories, the energy at which body weight would stay about the same.
How accurate is the estimate?▼
It is an estimate, and individual results can differ from it by 10% or more. Two people of the same age, height and weight can burn quite different amounts. People commonly overestimate how active they are, so if you are unsure choose the lower level. Treat the number as a starting point for your own observation, not a measurement.
Which activity level should I choose?▼
Choose the one that matches an ordinary week. 'Little or no exercise' fits a desk job with little walking. 'Light activity' means exercise one to three days a week, 'moderate' three to five days, 'high' six or seven days of hard exercise, and 'very high' a physical job plus hard training. Each level shows a short description to help.
Does age change the result?▼
Yes. In the formula, each extra year of age lowers the estimated BMR slightly, because the body on average needs a little less energy as it ages, often linked to loss of muscle. That is why the same height and weight gives a lower estimate at 60 than at 30. The formula is intended for adults aged 18 and over.
What does the 'compare your intake' box do?▼
It is simple subtraction. Type the calories you actually eat in a day and it shows how far that is above or below your estimated daily energy use. It does not tell you what you should eat. Body weight is affected by many factors beyond calories, so for advice about diet or weight, speak to a doctor or a registered dietitian.
Can I see the result in kilojoules?▼
Yes. Switch the energy unit to kJ. One kilocalorie equals 4.184 kilojoules. Kilojoules are used on food labels in Australia, New Zealand and parts of Europe.
Is this medical advice? Is my data stored?▼
It is general information only and not medical advice. Your details stay in your browser and are never uploaded or saved.