Macro calculator

How many grams of protein, fat and carbs a day for your goal: losing weight, maintaining or building muscle.

Calories a day to lose weight

1,584 calories

500 under the 2,084 you burn

Protein 117 g
Fat 44 g
Carbs 180 g

At 143 lb, to lose weight, this works out to about 1,584 calories a day: 117 g of protein, 44 g of fat and 180 g of carbs.

That’s 29% of your calories from protein, 25% from fat and 46% from carbs. Protein is 0.82 g per lb of body weight.

I’m not a doctor or a dietitian. This is an estimate, for information only. For decisions about your health, check with a professional.

Your numbers

example: change the numbers

Units

The math stays the same. Only the way the numbers are shown changes.

Metrickg · cmUSlb · ftUKst · ft

Your goal

Lose weight500 calories under what you burnMaintainwhat you burnBuild muscle10% over what you burn

Sex

The calorie formula has one version for men and one for women.

FemaleMale

Age

For adults: the calorie formula was built on people aged 19 to 78.

Height

Weight

Your weight today: protein is counted on it.

How active you are

Think of a typical week, including your job.

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Your macros in detail
Macro	Grams a day	Calories	Share	Per lb of body weight
Protein	117 g	467	29%	0.82 g per lb
Fat	44 g	396	25%	0.31 g per lb
Carbs	180 g	721	46%	1.26 g per lb
Total		1,584	100%

How it works

Calories first: what you burn in a day (resting burn with the Mifflin-St Jeor equation, times your activity), minus 500 to lose weight, the same to maintain, plus 10% to build muscle.
Protein: 1.8 g per kilogram of body weight (0.82 g per pound) to lose weight or build muscle, 1.4 g per kilogram (0.64 g per pound) to maintain. Fat: 25% of calories to lose or build, 30% to maintain. Carbs: whatever calories are left.
Calories are turned into grams with the standard factors used on US nutrition labels: 4 calories per gram of protein and of carbs, 9 per gram of fat.

Worked example

A moderately active 35-year-old woman, 5 ft 5 in and 143 lb (64.86 kg), who wants to lose weight: she burns 2,084 calories a day, so 2,084 − 500 = 1,584. Protein: 1.8 × 64.86 = 117 g (467 calories). Fat: 25% of 1,584 = 396 calories ÷ 9 = 44 g. Carbs: 1,584 − 467 − 396 = 721 calories ÷ 4 = 180 g.

Sources

Text checked on September 30, 2026

Good to know

The split is a starting point, not a prescription. The grams per kilogram and the fat shares are this calculator’s choices within the ranges in the sources, not a number any one source gives for everyone.
The Dietary Guidelines for Americans 2025–2030 set protein goals of 1.2 to 1.6 g per kg a day. Studies of people who train use 1.4 to 2.0 g, and 1.6 to 2.4 g while losing weight: the 1.8 used here for losing weight or building muscle is above the general goal and meant for people who exercise.
Protein is counted on your weight today. With a lot of weight to lose, that can add up to more than you need; if a warning appears, a registered dietitian can set a target that fits you.
For losing weight, the calorie deficit matters more than the exact split: US obesity guidelines found that many different diets work when they cut calories.
If you’re pregnant or breastfeeding, have a health condition or take medication, talk to your doctor before changing how you eat.

Frequently asked questions

How much protein do I need a day?

The minimum for adults, the RDA, is about 0.8 g per kilogram of body weight (0.36 g per pound). The Dietary Guidelines for Americans 2025–2030 set goals of 1.2 to 1.6 g per kilogram, and the International Society of Sports Nutrition suggests 1.4 to 2.0 g for most people who exercise. This calculator uses 1.4 to 1.8 depending on your goal.

What are the best macros for weight loss?

There’s no single best split. US obesity guidelines found that a variety of diets lead to weight loss when they cut calories, so the deficit comes first. Enough protein helps you keep muscle while you lose: reviews for people who train suggest 1.6 to 2.4 g per kilogram in a deficit.

Is a high-protein diet safe?

For healthy adults, EFSA considers up to twice its reference intake safe, about 1.7 g per kilogram a day, and hasn’t set an upper limit because the data are insufficient. If you have kidney disease or another health condition, ask your doctor before raising your protein.

How low can carbs go?

EFSA estimates that 130 g a day covers the brain’s need for glucose, and uses 45 to 60% of calories as its reference range for adults. Going lower is a choice to make with your doctor or a registered dietitian.

Why do the calories change with the goal?

To lose weight, the calculator takes 500 calories off what you burn, the deficit used in US obesity guidelines. To build muscle, it adds 10%, the low end of the 10 to 20% surplus suggested in a review for natural bodybuilders. To maintain, it’s what you burn.