Calculadora IIFYM
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
35% carbo, 40% prot, 25% gord (split clássico IIFYM)
About this calculator
The IIFYM (If It Fits Your Macros) Calculator is a tool that calculates macronutrient distribution (carbohydrates, proteins, and fats) based on a flexible percentage split. By default, we use the ratio 35% carbohydrates, 40% protein, and 25% fat, a classic IIFYM split. The calculator takes a daily total calorie value (entered manually or from another tool) and converts these percentages into grams of each macronutrient, using conversion factors: 4 kcal/g for carbs and protein, and 9 kcal/g for fat.
The IIFYM method is based on the idea that no foods are forbidden as long as macronutrient and calorie amounts are respected. This makes the diet more flexible and sustainable for many people, especially those who struggle with restrictive eating plans. The calculator is useful for creating a personalized diet, whether for weight loss, muscle gain, or weight maintenance, as long as the total calorie intake is adjusted to the goal.
When to use? Ideal for athletes, bodybuilders, and anyone wanting to control macronutrient intake without giving up a variety of foods. It is also useful for those following flexible dieting or macro counting. Cautions: the default percentages may not be suitable for everyone; individuals with specific health conditions (such as diabetes or kidney problems) should consult a nutritionist before adopting this split. Additionally, food quality still matters, it's not just about hitting macros.
Frequently asked questions
What does IIFYM stand for?
IIFYM stands for "If It Fits Your Macros." It is an approach that allows any food in your diet as long as your carbohydrate, protein, and fat amounts stay within daily targets.
Does this calculator replace a nutritionist?
No. The calculator is a reference tool for macro distribution, but it does not replace professional assessment. Each person has individual needs that should be evaluated by a nutritionist.
Can I change the percentages?
Yes. The default split is 35/40/25, but you can adjust the percentages according to your goals or professional recommendations. Just enter different values in the corresponding fields.
What foods are allowed on IIFYM?
All foods are allowed as long as you respect macro and calorie targets. However, it is recommended to prioritize nutrient-dense foods to ensure adequate vitamins and minerals.
Does IIFYM work for weight loss?
Yes, as long as total calories are in a deficit. The macro distribution helps with satiety and muscle preservation, but the main factor for weight loss is a negative calorie balance.