How do you convert calories into grams of macros?

Use the Atwater factors: carbohydrate and protein each supply 4 calories per gram, and fat supplies 9. To find grams of a macro, take your calorie target, multiply by that macro's percentage, then divide by its calories-per-gram. For example, 30% protein of a 2,000-calorie diet is 600 calories, and 600 ÷ 4 = 150 grams of protein. Carbs use the same divisor; fat divides by 9.

What is a good macro split?

There is no single best split — it depends on your goal and what you can stick to. A balanced 40/30/30 (carb/protein/fat) suits most people. Cutting fat lower (40/40/20) raises protein for muscle retention; going low-carb or keto pushes fat up and carbs down for appetite control. Protein is the macro that matters most for body composition, so set that first and let carbs and fat fill the rest.

How much protein should I eat?

A common range for active people is 1.6 to 2.2 grams of protein per kilogram of body weight per day (about 0.7 to 1.0 grams per pound). On a calorie-percentage basis that usually lands between 25% and 40% of calories. Protein protects muscle in a deficit and supports growth in a surplus, so most lifters treat it as a floor to hit rather than a number to split evenly. Our protein calculator works it out from your weight.

Can my macro percentages not add up to 100?

They have to — the three macros account for all of your calories, so their percentages must total 100%. If your custom split adds up to more or less, the grams won't match your calorie target. The calculator flags the sum live and offers a one-tap 'Scale to 100%' that keeps your proportions but normalizes them, so a 50/40/40 idea becomes a clean split that still respects what you wanted more of.

Why is fat 9 calories per gram and not 4?

Fat is a more energy-dense molecule than carbohydrate or protein — it packs more chemical energy per unit of mass, so burning a gram of it releases roughly 9 calories versus 4. That's why a low-fat split yields far more total grams of food at the same calories, and why a tablespoon of oil 'costs' more than it looks. It's not that fat is bad; it's just calorie-dense, so small amounts add up fast.

Do I need to hit my macros exactly every day?

No. Treat your macros as targets to land near, not bullseyes. Being within five to ten grams of each is close enough for almost everyone, and what matters is the weekly average, not a single day. Obsessing over the last gram causes more harm than missing it. Hit your protein, keep calories in the right zone, and let carbs and fat flex with your day.

How do I figure out my calorie target?

Macros start from a calorie number, so you need that first. Your maintenance calories — your TDEE — come from your basal metabolic rate scaled by how active you are; then you add or subtract a few hundred to lose or gain. The calculator has a built-in estimator, or use our dedicated TDEE calculator for the full breakdown. Once you have the calorie target, the split turns it into grams.

Health

Macro Calculator

Turn a daily calorie target into grams of carbs, protein, and fat. Pick a diet split — balanced, low-carb, high-protein, or keto — or set your own percentages. See per-meal grams and the full working, updated live.

Your daily target

Set your calories and how you want them split.

Daily calories

kcal

Diet split

Carbs

Protein

Fat

Sum: 100% ✓

Meals per day

Carbs

200 g

800 kcal · 40%

Protein

150 g

600 kcal · 30%

Fat

67 g

600 kcal · 30%

2,000 kcal total40% / 30% / 30%

Per meal (÷ 4)

Carbs 50 gProtein 38 gFat 17 g

Try an example

No sign-up · Free

The basics

What are macros?

Macronutrients — macros — are the three energy-supplying parts of food: carbohydrate, protein, and fat. Your calorie total tells you how much to eat; your macros tell you what kind. Two diets at the same calories can feel and perform completely differently depending on how those calories are split.

calories = the budget

Calories are the total

Your daily calorie target is the size of your energy budget — it decides whether you lose, hold, or gain weight. It says nothing, on its own, about the food behind it.

2,000 kcal/day to spend

macros = how you spend it

Macros are the breakdown

The split divides that budget into grams of each macro. The same total can lean toward carbs for training, protein for muscle, or fat for satiety — that choice is the macro split.

carbs · protein · fat, in grams

Method

How to calculate your macros by hand

Three steps turn a calorie number into grams. The calculator does it instantly, but the arithmetic is simple enough to check on paper.

1
Set your calorie target
Start from a daily calorie figure — your maintenance, or a deficit/surplus for your goal. Everything downstream scales from this one number.
e.g. 2,000 kcal/day
2
Pick a percentage split
Choose how much of those calories comes from each macro. The three percentages must add to 100% — protein first, then carbs and fat fill the rest.
40% carb · 30% protein · 30% fat
3
Convert each share to grams
Multiply calories by each macro's percentage, then divide by its calories-per-gram — 4 for carbs and protein, 9 for fat.
grams = kcal × % ÷ kcal-per-g

Worked examples

The same calories, five different splits

Take a 2,000-calorie day and run it through each diet template. Only the percentages change — watch how the grams of each macro shift.

Given 2,000 kcal at 40/30/30 (carb/protein/fat)

Carbs: 2000 × 40% ÷ 4 = 200 g (800 kcal)

Protein: 2000 × 30% ÷ 4 = 150 g (600 kcal)

Fat: 2000 × 30% ÷ 9 = 67 g (600 kcal)

Carbs 200 gProtein 150 gFat 67 g

Reference

The factors and the standard splits

Two pieces of fixed data sit behind every result: the calories each macro supplies per gram, and the percentage templates the popular diets use.

Carbohydrate

4 kcal/g

Starches & sugars

Protein

4 kcal/g

Meat, dairy, legumes

Fat

9 kcal/g

Oils, nuts, fatty cuts

Split	Carb	Protein	Fat	Best for
Balanced	40%	30%	30%	Everyday all-rounder
Low fat	60%	25%	15%	Higher carb, leaner fat
Low carb	25%	40%	35%	Fewer carbs, more fat
High protein	40%	40%	20%	Muscle-building / cutting
Keto	5%	30%	65%	Very low carb, high fat

Where it shows up

Why the split matters

The same calories serve different goals depending on how you divide them. Three common cases.

cutting

Losing fat, keeping muscle

In a deficit, protein goes high to spare muscle and carbs fuel training. A high-protein or low-carb split makes the diet easier to hold and protects your hard-won muscle. Set your calories with the TDEE calculator.

bulking

Building muscle

In a surplus, carbs climb to power heavy training and recovery, protein stays high to build, and fat fills the rest. Dial in your protein floor with the protein calculator.

keto

Low-carb & keto

Keto flips the ratio: fat dominates, carbs drop near zero, protein sits moderate. The body shifts to burning fat for fuel. The math is the same — just a very different split.

Worth knowing

Where splits go wrong

A percentage split is a starting point, not a law. A few realities keep your macros sensible.

protein has a floor

Set protein first

Protein is the macro that decides body composition, so most people fix it as a gram target from body weight, then split the leftover calories between carbs and fat. A pure percentage can leave protein too low on a small calorie budget.

fat has a minimum

Don’t starve fat

Fat below roughly twenty percent of calories can disrupt hormones and the absorption of fat-soluble vitamins. Very low-fat splits look efficient on paper but can backfire on health and recovery.

fiber matters

Carbs aren’t all equal

A gram of carbohydrate from vegetables and whole grains behaves nothing like a gram from soda. Macros count quantity, not quality — fiber and food source still matter for fullness, digestion, and health.

a starting point

Splits are estimates

These templates are sensible defaults, not prescriptions. Adjust by how you feel, train, and progress. The best split is the one you can keep, that hits your protein, and that lands your calories where they need to be.

Quick chart

Macros at common calorie targets

Grams of carbs, protein, and fat for a balanced 40/30/30 split across the calorie levels most people land on. Find your row and read off the grams.

Daily calories	Carbs	Protein	Fat
1,200	120 g	90 g	40 g
1,500	150 g	113 g	50 g
1,800	180 g	135 g	60 g
2,000	200 g	150 g	67 g
2,200	220 g	165 g	73 g
2,500	250 g	188 g	83 g
2,800	280 g	210 g	93 g
3,000	300 g	225 g	100 g

Balanced split — 40% carbs · 30% protein · 30% fat. Carbs and protein at 4 kcal/g, fat at 9 kcal/g.

FAQ

Common questions

Macros — short for macronutrients — are the three components of food that supply energy: carbohydrate, protein, and fat. Every calorie you eat comes from one of them (alcohol aside). A macro calculator takes a daily calorie target and divides it into grams of each, so you know not just how much to eat but what kind. The split you choose shapes how you feel, train, and recover, even at the same calorie total.

Keep going

Related calculators

Guide

Macros for weight loss: protein, carbs & fat

Guide

How many calories to lose weight

Keep reading

Your daily target