Free macro calculator

1. Base Calorie Calculation

We estimate resting energy with the Mifflin–St Jeor equation. Predictive equations are convenient population-level tools, but studies show meaningful individual error compared with indirect calorimetry.

2. Activity Level Adjustment

Your BMR is then multiplied by an activity factor:

• Sedentary (little exercise): × 1.2
• Lightly active (light exercise 1-3 days/week): × 1.375
• Moderately active (moderate exercise 3-5 days/week): × 1.55
• Very active (hard exercise 6-7 days/week): × 1.725
• Extra active (very hard exercise & physical job): × 1.9

3. Goal Adjustment

Your calories are then adjusted based on your goal:

• Weight loss: estimate a 0.5% weekly rate, capped at a 20% calorie reduction
• Weight Maintenance: No change
• Weight gain: estimate a 0.5% weekly rate, capped at a 20% calorie increase

4. Macro Split

The current calculator divides estimated calories into one general adult starting point:

• 30% protein, 45% carbohydrates, and 25% fat

Each gram of protein and carbs provides 4 calories, while each gram of fat provides 9 calories.

What is a macro calculator?

A macro calculator is a tool that estimates daily protein, carbohydrate, and fat targets in grams. It uses your weight, height, age, sex, activity level, and goal to compute Total Daily Energy Expenditure (TDEE), then splits that calorie target into the three macronutrients.

How accurate is the Mifflin–St Jeor equation?

It is a widely used estimate, not a measurement. Accuracy varies with population and body composition, so compare the estimate with real weight and intake trends over several weeks.

Is one macro split right for everyone?

No. The 30/45/25 result is a simple starting point within general adult macronutrient ranges, not a universal prescription. Preferences, training, medical needs, and tolerance can justify a different distribution.

When should I get individual guidance?

Consult a qualified professional if you are under 18, pregnant or breastfeeding, managing a health condition, taking medication that affects metabolism, or have a current or past eating disorder.

Is the kkal.ai macro calculator free?

Yes. The macro and BMR calculators are free to use on the web without an account. Meal-photo tracking is available in the kkal.ai mobile apps.

How is this different from a calorie calculator?

A calorie calculator gives a daily energy estimate. A macro calculator then converts that estimate into protein, carbohydrate, and fat grams using a selected distribution. The result is still a planning estimate, not a prediction of body-composition change.