How many carbs should I eat?

Carbs are the flexible macro — after setting protein and fat, carbs fill the remaining calories. Most people do well with 40–50% of calories from carbs. Endurance athletes may need more; low-carb dieters intentionally eat less.

What is the 40/30/30 macro split?

40% carbs, 30% protein, 30% fat is a popular starting point. It works well for many goals but isn't optimal for everyone. Prioritize hitting your protein target first, then adjust carbs and fat to preference.

Do macros matter more than calories?

For weight change, total calories matter most. For body composition (muscle vs. fat), macros — especially protein — matter significantly. Hitting your calorie target with adequate protein gives the best of both.

IIFYM stands for 'If It Fits Your Macros.' It's a flexible dieting approach where any food is allowed as long as your daily macro targets are hit. It works well for adherence but requires accurate tracking.

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Macro Calculator

Calculate your daily protein, carb, and fat targets in grams. Uses a protein-first approach tailored to your goal — weight loss, maintenance, or muscle gain.

Last updated: April 13, 2026

How to Use This Calculator

Enter your sex, age, height, weight, and activity level.
Select your goal: weight loss, maintenance, or muscle gain.
Review your daily calorie target and macro breakdown in grams.
Use the macro targets to plan your meals and track your nutrition.

Real-World Examples

Weight Loss Macros

160 lb woman, 1,600 kcal/day deficit target, weight loss goal.

Result: Protein: 160 g (640 kcal). Fat: 44 g (400 kcal). Carbs: 140 g (560 kcal). Split: ~35P / 25F / 35C.

Muscle Gain Macros

180 lb man, 3,000 kcal/day surplus target, muscle gain goal.

Result: Protein: 180 g (720 kcal). Fat: 83 g (750 kcal). Carbs: 383 g (1,530 kcal). Split: ~24P / 25F / 51C.

Common Mistakes to Avoid

Prioritizing carb and fat targets before hitting protein — protein is the most important macro to get right.
Using gram targets without tracking — eyeballing portions leads to large macro errors.
Not adjusting macros as bodyweight changes — your gram targets should scale with your weight.
Forgetting that dietary fat has 9 kcal/g, not 4 — fat is calorie-dense and easy to over-consume.

The Formula

Protein: 1 g per lb of bodyweight (weight loss/gain goals) or 0.8 g per lb (maintenance). Fat: 25% of total calories (weight loss/gain) or 30% (maintenance). Carbs: remaining calories ÷ 4. All values use the Atwater system: protein = 4 kcal/g, carbs = 4 kcal/g, fat = 9 kcal/g.

Learn More

Health

Best Macro Split for Weight Loss vs Muscle Gain

The best macro split depends on your goal. Here's what the research says.

April 13, 2026

Frequently Asked Questions

For most active adults, 0.7–1 g of protein per lb of bodyweight (1.6–2.2 g/kg) supports muscle maintenance and growth. Higher protein intake is especially important during a calorie deficit to prevent muscle loss.