Nutrition Calculators
Calculate BMR, calorie and calorie deficit and other nutrition calculations.
Most nutrition calculators here build on one number: the calories you burn in a day. Start there, adjust it for your goal, and only then split it into protein, carbohydrate and fat — otherwise the macro numbers rest on a guess.
Which Nutrition calculator do you need?
- How many calories do I burn in a day?Calorie CalculatorBMR from the Mifflin-St Jeor equation, multiplied by your activity level.
- How many calories should I eat to lose weight?Calorie Deficit CalculatorSubtracts a daily deficit matched to your target weekly loss.
- How many calories should I eat to gain weight or muscle?Calorie Surplus CalculatorAdds a daily surplus matched to your target weekly gain.
- How do I split my calories into macros?Macro CalculatorConverts a calorie target and percentage split into grams of protein, carbohydrate and fat.
- How much protein do I need?Protein Intake CalculatorA daily range from bodyweight and activity level.
- How much water should I drink?Water Intake CalculatorA daily estimate from bodyweight plus exercise time.
All Nutrition Calculators
Order matters
Work out maintenance calories first, then the deficit or surplus for your goal, then the macro split. Protein is usually set by bodyweight rather than as a percentage, so it is worth running the protein calculator and fitting carbohydrate and fat around it.
Limitations
- Equations estimate averages; individual needs vary, and medical conditions change them.
- Not a substitute for advice from a doctor or registered dietitian.
Nutrition Guides
How Calorie Deficit and Surplus Targets Are Calculated
A calorie deficit or surplus target is your maintenance calories, adjusted up or down by a daily amount derived from your desired weekly rate of weight change, using the approximation that 1kg of body fat holds about 7,700 kcal.
Read guideHow Daily Fiber Recommendations Are Determined (By Age and Sex)
Recommended daily fiber intake varies by both age and sex, following the U.S. Institute of Medicine's Adequate Intake values — the recommendation for males rises through childhood into adulthood before declining in older age, while the female recommendation stays comparatively flat and consistently lower than the male recommendation from adolescence onward.
Read guideHow Daily Water Intake Is Calculated
Recommended water intake is a baseline tied to bodyweight, plus an extra allowance for exercise that scales directly with how many minutes were spent sweating that day.
Read guideHow Macronutrient Grams Are Calculated From Calorie Percentages
Converting a macro split (like "30% protein, 40% carbs, 30% fat") into actual grams requires dividing by each macronutrient's specific calories-per-gram value — protein and carbs at 4 kcal/g, fat at 9 kcal/g — which is why an identical percentage of daily calories converts to very different gram amounts depending on which macronutrient it's for.
Read guideHow Much Protein Do You Actually Need? Activity Level Changes the Answer
Recommended daily protein intake is commonly expressed as a range in grams per kilogram of body weight, and that range scales substantially with activity level — for the identical body weight, an athlete's recommended range is more than double a sedentary person's, since higher training volume increases the body's protein needs for muscle repair and maintenance.
Read guide