Health & nutrition calculators
Free, science-based tools to estimate your calories, macros, and more — then put the numbers to work by tracking your meals with Caltrac.
Calorie / TDEE calculator
Find your daily calorie needs (TDEE) and a target for your goal.
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BMR calculator
Estimate your resting energy expenditure (basal metabolic rate).
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Macros calculator
Turn your calorie target into daily protein, carbs, and fat.
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BMI calculator
Check your Body Mass Index and weight category.
Open calculatorWhich calculator should you start with?
If you only use one, use the calorie calculator. It works out your BMR, then multiplies it by your activity level to get your TDEE: the number of calories you burn on a normal day. Eat below that and you lose weight. Eat above it and you gain.
The macro calculator picks up from there. Give it your calorie target and it splits it into protein, carbs and fat. By default it sets protein at 1.8 g per kg of body weight and fat at 30% of calories, with carbs filling the rest, and you can adjust both.
The BMR calculator is useful on its own if you want to see what your body burns at complete rest. BMI is a quick screening number from your height and weight. It doesn’t know how much of your weight is muscle, so treat it as a rough guide, not a verdict.
All of these are estimates built on the Mifflin–St Jeor equation, the formula most dietitians use. Your real needs can be a few hundred calories off. The way to find out is to track what you eat for two or three weeks and watch what your weight does.