Macro Calculator (Protein, Fat, Carb Split)

Enter your daily calorie target and a macro ratio (protein, fat, carbohydrate) to get the target grams for each. Choose a balanced, high-protein, or low-carb preset, or set your own custom ratio.

What Is a Macro Calculator?

A macro calculator splits your daily calorie target into grams of protein, fat, and carbohydrate — the three macronutrients, often called "macros" for short. Rather than tracking calories alone, paying attention to how those calories are split between macros makes it easier to tailor your eating for goals like fat loss, muscle maintenance, or performance.

This tool offers three common presets — Balanced, High Protein, and Low Carb — plus a Custom mode where you set your own ratio. If you already have a calorie target from health.calc.calorie (Calorie Calculator), you can enter it directly here to go from total calories to a full macro breakdown in one step.

How to Use

Enter your daily calorie target Type in how many calories you want to eat per day. You can use the TDEE, cut, or bulk value from health.calc.calorie.
Choose a macro ratio Pick Balanced, High Protein, or Low Carb, or switch to Custom to set your own ratio.
Adjust the ratio (Custom mode only) Move the protein, fat, and carb sliders so they add up to 100%.
Check the results The target grams and calories for each macronutrient are shown in a table.

Tips for getting more out of it

In Custom mode, protein, fat, and carb percentages must add up to 100%. If they do not, no result is shown.
If you raise your protein percentage significantly, lower fat or carbohydrate by a matching amount to keep the total at 100%.
If you do not yet know your calorie target, calculate your TDEE or cut/bulk target with health.calc.calorie first, then bring that number here.
Keeping fat percentage very low (under 10%) for extended periods has been linked to issues with fat-soluble vitamin absorption and hormone balance, so it is best to adjust this with guidance from a professional.

Common Use Cases

Managing meals during a cut

Combine a calorie deficit with the High Protein preset to help preserve muscle while losing fat.

Nutrition planning for strength training

Increase your protein target to match your training volume using the High Protein preset or a custom ratio.

Setting up a low-carb diet

Use the Low Carb preset to see roughly how many grams of carbohydrate per day fit your target.

Planning calories and macros for a bulk

Enter your bulking calorie target and check the macro breakdown under the Balanced or High Protein ratio.

Glossary

Macro ratio: The percentage split of your daily calories between protein, fat, and carbohydrate — the three macronutrients, commonly called "macros."
Atwater factors: The conversion factors used to turn grams of a macronutrient into calories: 4 kcal/g for protein and carbohydrate, and 9 kcal/g for fat.
TDEE: Total Daily Energy Expenditure — your total daily calorie burn, including your basal metabolic rate plus activity. You can calculate it with health.calc.calorie.
High protein: A macro split with a higher-than-typical protein percentage, often used to help preserve or build muscle.
Low carb: A macro split with a lower-than-typical carbohydrate percentage, used when reducing carbohydrate intake is a goal.

Frequently Asked Questions

General dietary guidelines commonly cite a range of roughly 10–35% protein, 20–35% fat, and 45–65% carbohydrate. The Balanced preset in this tool (15% protein, 25% fat, 60% carbohydrate) falls within that commonly cited range.

As long as the total is off by more than 0.5 percentage points from 100%, no result is shown, and a message asks you to adjust the sliders so the total equals 100%.

Your calorie target is multiplied by each macro percentage to get calories per macro, and that figure is divided by the Atwater factor (4 kcal/g for protein and carbohydrate, 9 kcal/g for fat) to get grams.

High Protein is a common choice when preserving or building muscle is the priority, while Low Carb is used when reducing carbohydrate intake is the goal. Both are general starting points — the right ratio depends on your body and goals, so consider consulting a professional if needed.

No. All calculations run entirely in your browser, and nothing you enter is sent to or stored on a server.

Side Note — Where the Term "Macros" Comes From

Protein, fat, and carbohydrate are called "macronutrients" because the body needs them in relatively large amounts, in contrast to "micronutrients" like vitamins and minerals, which are needed only in small amounts. "Macros" is simply the informal short form that took hold in fitness and nutrition circles.

The Atwater factors used to convert grams of each macronutrient into calories — 4 kcal/g for protein and carbohydrate, 9 kcal/g for fat — trace back to metabolic experiments conducted by the American chemist Wilbur Olin Atwater in the late 19th and early 20th centuries. It is a small reminder of nutrition science's history that figures established more than a century ago are still the basis for everyday calorie math today.

Dietary guidelines generally present macro ratios as a range rather than a single fixed number, reflecting the fact that the ideal split depends on an individual's body, activity level, and goals. Adjusting protein and carbohydrate ratios to match specific training goals is a relatively recent practice that spread from competitive bodybuilding and sports nutrition into everyday fitness tracking.

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