Nutrition Calculators

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.

How 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.

How 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.

How 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.

How 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.