IIFYM Macro Calculator

About this calculator

IIFYM ('If It Fits Your Macros') is a flexible dieting approach that sets daily targets for the three macronutrients — protein, carbohydrate, and fat — while leaving food choice largely open, on the premise that body composition change is driven primarily by total calories and macronutrient totals rather than by which specific foods those macros come from. Targets are typically set by choosing a protein intake per unit of body weight and a fat percentage of total calories, with the remaining calories filled in as carbohydrate.

The approach was popularized within bodybuilding and physique communities as a reaction against rigid 'clean eating' meal plans, and is now widely used by recreational lifters and coaches who want structured nutrition targets without prescribing specific foods, letting dieters fit foods like treats or convenience meals into their plan as long as the daily macro totals are met.

This calculator takes your daily calorie target and chosen protein and fat percentages and returns your daily protein, carbohydrate, and fat targets in grams for an IIFYM flexible diet.