IIFYM Calculator (If It Fits Your Macros)

IIFYM means “If It Fits Your Macros”: recording foods against chosen carbohydrate, protein and fat amounts. This calculator converts your own energy target and split; the name of the approach is not evidence that a split is appropriate for a particular person.

Macro totals alone do not describe vitamins, minerals, fiber, allergens or the suitability of a food for a medical diet.

1. Enter a calorie target you have already chosen. This tool does not estimate energy needs from your age, weight, activity, or goals.
2. Choose carbohydrate, protein and fat percentages totaling 100%. A change to one percentage does not silently change another.
3. Convert each percentage to a fraction, multiply by the entered calories, then divide carbohydrate and protein calories by 4 and fat calories by 9.

Worked example: 2,000 kcal with carbohydrate 50%, protein 20%, fat 30% yields 250 g carbohydrate, 100 g protein and 66.7 g fat. The fat value is rounded for display; calculations use the unrounded amount.

The general 4/4/9 convention assigns 4 kcal/g to carbohydrate and protein and 9 kcal/g to fat. 21 CFR 101.9(c)(1) also describes other food-energy methods and specific factors for fiber and polyols. The chosen convention here is conditional planning arithmetic, not a reconstruction of every food label. Checked September 30, 2026.

Health Canada dietary reference values give AMDRs (Acceptable Macronutrient Distribution Ranges): ages 19+ carbohydrate 45–65%, protein 10–35%, fat 20–35%; ages 4–18 protein 10–30% and fat 25–35%; ages 1–3 protein 5–20% and fat 30–40%. Carbohydrate remains 45–65% for ages 1–18. These population references do not choose a personal menu. Table updated November 19, 2025; checked September 30, 2026.

Food examples include grains, vegetables, fruit and legumes for carbohydrate; fish, eggs, dairy, soy and legumes for protein; and oils, nuts, seeds and avocado for fat. Foods usually contain more than one macro, so record all declared amounts.

Tracking can make the relationship between portions, calories and macro grams easier to see. It also requires consistent serving sizes and accurate entries. Matching three numbers does not certify food quality or guarantee a weight-loss rate.

Label values are rounded, and generic food records may describe a different preparation. Identify the actual food and quantity before comparing a meal with your entered scenario.

1. Enter your independently chosen calorie target and all three macro percentages.
2. Review the displayed formula and grams before using them in a meal record.
3. For each food, record its quantity and nutrition values on the same serving or weight basis.
4. Include all macro contributions, including those from sauces, drinks and mixed foods.
5. Review fiber, micronutrients and ingredients separately; they are not certified by matching macro totals.