IIFYM Calculator
IIFYM — "if it fits your macros" — is a flexible way of eating where you hit daily targets for protein, fat and carbs rather than following a fixed menu. This calculator sets those targets the way the approach usually does: protein from your body weight, then fat, then carbs.
Don't know your calories? Use the Calorie Calculator. Exercising regularly? ISSN suggests 1.4–2.0 g protein per kg.
Protein
g
%
Fat
g
%
Carbs
g
%
Protein = weight × g/kg · fat = calories × % ÷ 9 · carbs = what's left ÷ 4 (Atwater factors, FAO 2003).
Your results are attached to the form below
These figures are estimates for general awareness only and are not medical advice or a diagnosis. Read our Medical Disclaimer.
Want a Plan Built Around Your Numbers?
A certified dietitian will turn these figures into a diet that fits your routine and your food.
How this is calculated
Protein = body weight × your chosen g/kg, from ICMR-NIN's 0.83 g/kg baseline up to the 1.4–2.0 g/kg the International Society of Sports Nutrition gives for people who exercise. Fat = your chosen share of calories (20–35%, the US Institute of Medicine range) ÷ 9. Carbs = the calories left ÷ 4. Results are flagged if carbs fall under the 130 g daily minimum or 45% of calories, or if protein goes over 35% of calories.
How IIFYM differs from a percentage split
The Macro Calculator divides your calories by percentage — say 20% protein. IIFYM starts from your body weight instead, so a heavier or more active person gets more protein whatever their calorie target, and carbs absorb the difference. On a low calorie target that can push carbs below recommended levels, which is why the calculator flags it.
Flexible, but not a free-for-all
Hitting your macros with packaged snacks is not the same as hitting them with dal, vegetables, curd and whole grains. Use the numbers as a frame, and fill it mostly with whole foods.
Related calculators
Check your protein needs on the Protein Calculator, or plan a very-low-carb version with the Keto Calculator.
More Diet & Nutrition Calculators
See all →- Protein Calculator Find your daily protein requirement using ICMR-NIN 2020, with separate figures for exercise, age 65+, pregnancy and breastfeeding.
- Calorie Deficit Calculator See your maintenance calories and a daily calorie target for weight loss, with two BMR formulas side by side.
- Macro Calculator Split your daily calories into grams of protein, carbohydrate and fat — balanced, higher-protein or your own ratio.
- Calorie Calculator How many calories do you need a day? See three recognised methods side by side — the clinic's, the US standard and India's ICMR-NIN.
- TDEE Calculator Your total daily energy expenditure with four BMR equations compared, and a breakdown of how much goes on rest, digestion and activity.
- Maintenance Calorie Calculator The calories that keep your weight steady — today, and at your goal weight, so you know what to eat once you get there.