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Calorie & BMR Calculator — Free Online Tool
This calorie calculator estimates how many calories your body burns in a day so you can plan meals around a goal. It first computes your basal metabolic rate, the energy your body needs at complete rest, using the revised Harris-Benedict equation with your sex, age, weight in kilograms and height in centimetres. That number is then multiplied by an activity factor, from 1.2 for a desk job with little exercise up to 1.9 for very hard training, to produce your total daily energy expenditure. Eating roughly that many calories keeps your weight stable. The result also shows a calorie target about five hundred below maintenance for losing around half a kilogram a week and five hundred above it for gaining weight gradually. The Harris-Benedict formula is an estimate and can be off by ten percent or more, particularly for very muscular, very lean or older users, so use it as a starting point and adjust according to how your weight changes over two to three weeks. It does not replace advice from a doctor or dietitian, especially if you have a medical condition, are pregnant or are planning an aggressive deficit. All calculations run in your browser and none of your personal data is stored or sent anywhere.
Use our Calorie & BMR Calculator on AllConvertor — no registration, no download, works on iPhone, Android, Windows, and Mac. All processing runs in your browser when possible for maximum privacy and speed.
How to use Calorie & BMR Calculator
- Choose male or female.
- Enter your age, weight in kg and height in cm.
- Select the activity level that matches your week.
- Read your BMR and maintenance calories.
- Use the lose or gain targets as a starting plan.
Key benefits
- ✓ 100% free — no paywall or trial limits
- ✓ No account or email required
- ✓ Mobile-friendly responsive design
- ✓ Instant results in your browser
- ✓ Secure — data stays on your device
- ✓ Trusted by thousands of users daily
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Frequently Asked Questions
What is BMR?
Basal metabolic rate is the number of calories your body burns at complete rest to keep breathing, circulating blood and maintaining temperature. It is the baseline used to work out your daily calorie needs.
Which Harris-Benedict equation does this use?
It uses the revised 1984 Harris-Benedict equations, which are considered more accurate than the original 1919 version. Separate constants are used for men and women.
How many calories should I eat to lose weight?
A common approach is to eat about 500 calories below your maintenance level, which leads to roughly 0.5 kg of fat loss per week. Avoid going below your BMR without medical supervision.
How accurate is the calorie result?
It is an estimate that can be off by around 10%. Track your weight for two to three weeks and raise or lower calories if your progress differs from the prediction.
Which activity level should I choose?
Pick sedentary if you mostly sit, lightly active for 1-3 workouts per week, moderately active for 3-5, very active for 6-7 and extra active only for athletes or physical labour.