Free macro calculator. Split your daily calorie target into grams of protein, carbs, and fat using a custom ratio or a common preset like balanced, low-carb, or keto.
A macro calculator converts a daily calorie target into grams of protein, carbohydrates, and fat based on a chosen percentage split. It multiplies your total calories by each macro's percentage to get that macro's calories, then divides by its energy density — 4 calories per gram for protein and carbs, 9 calories per gram for fat — to get the gram target.
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Daily calories
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Macro Calculator
A daily calorie target tells you how much energy to eat, but it doesn't tell you what to eat it as. Macronutrients — protein, carbohydrates, and fat — are the three categories that make up all food calories, and splitting your target calories among them in specific gram amounts is what makes a nutrition plan actually trackable day to day.
This calculator takes your daily calorie target and a percentage split between the three macros, then converts each percentage into a concrete gram target using each macro's calorie density: 4 calories per gram for protein and carbs, 9 calories per gram for fat.
Why the Math Works This Way
Converting a macro percentage into grams is a two-step calculation. First, multiply total calories by the macro's percentage to find how many calories that macro should contribute — a 30% protein split at 2,000 calories means 600 calories should come from protein. Second, divide that calorie amount by the macro's energy density in calories per gram to get the gram target — 600 protein calories ÷ 4 calories per gram = 150 grams of protein.
The same process applies to carbs (also 4 calories per gram) and fat (9 calories per gram, since fat is more energy-dense). This calculator runs that conversion for all three macros simultaneously, so adjusting the calorie target or any percentage instantly updates all three gram targets.
Common Splits
Different eating approaches use different macro splits. A "balanced" split (often around 30% protein, 40% carbs, 30% fat) spreads calories relatively evenly and works as a general-purpose starting point. A high-protein split shifts more calories toward protein (often 35-40%) to support muscle retention, common during a calorie deficit or for strength training goals.
Low-carb approaches reduce carbohydrate percentage significantly (often to 20% or less) while increasing fat, and ketogenic diets push this further — typically under 10% carbs — to shift the body's primary fuel source toward fat-derived ketones. None of these splits is universally "correct"; the right one depends on individual goals, activity level, and personal preference for what's sustainable to follow.
Limitations
This calculator only converts a calorie target and percentage split into grams — it doesn't calculate your calorie target itself or recommend which macro split is right for your goals. For your daily calorie needs based on your body stats and activity level, see our TDEE calculator or calorie calculator first, then bring that number here to set your macro breakdown.
It also doesn't account for fiber (a carbohydrate subtype with minimal usable calories), alcohol (7 calories per gram, not modeled here), or micronutrient needs, all of which matter for a complete nutrition plan beyond macro grams alone.
Practical Use Cases
Setting up a tracking app
Getting exact gram targets to enter into a food tracking app like MyFitnessPal or Cronometer.
Following a specific diet plan
Converting a diet's percentage recommendations (like keto or a high-protein plan) into grams you can measure.
Meal planning and prep
Working backward from gram targets to plan meals that hit your protein, carb, and fat goals.
Adjusting for a new calorie target
Recalculating gram targets after a calorie target changes due to a new weight goal or activity level.
Comparing different macro approaches
Seeing the gram difference between a balanced split and a low-carb or high-protein split at the same calorie level.
Multiply your total daily calories by each macro's percentage to get that macro's calorie share, then divide by its energy density: protein and carbs are 4 calories per gram, fat is 9 calories per gram. For example, at 2,000 calories with a 30% protein split: 2,000 × 0.30 = 600 protein calories, and 600 ÷ 4 = 150 grams of protein.
These are standard Atwater factors, based on how much usable energy the body extracts from each macronutrient during digestion. Protein and carbohydrates provide about 4 calories per gram, while fat provides about 9 calories per gram — more than double — because fat is a more energy-dense molecule.
There's no single universally optimal split for weight loss — total calorie deficit matters more than the specific macro ratio for fat loss. That said, higher protein intake (30-40% of calories) is commonly recommended during a calorie deficit to help preserve muscle mass, with the remaining calories split between carbs and fat based on personal preference and training demands.
A ketogenic diet typically targets very low carbohydrate intake (often under 10% of calories, sometimes as low as 5%), moderate protein (20-25%), and high fat (65-75%) — the low carb intake is designed to shift the body's primary fuel source from glucose to fat-derived ketones.
Yes — since every calorie in your daily target needs to come from one of the three macronutrients, the percentages must sum to 100%. This calculator warns you if your current protein, carb, and fat percentages don't add up correctly so you can adjust them.