Macro Calculator

What are macros, really?

Macronutrients — protein, carbohydrates, and fat — are the three nutrients your body needs in large amounts, and the only three (besides alcohol) that provide calories. Get your calories right and your weight moves in the direction you want. Get your macros right and you control what that weight change is made of: whether you lose fat while keeping muscle, or lose both; whether you gain muscle lean, or get soft.

This is why “a calorie is a calorie” is only half true. For fat loss and body composition, the split — especially how much protein you eat — changes the outcome dramatically. If you have not set your calories yet, run the TDEE Calculator first, then come back here to turn that number into a plan.

The three macros and what they do

Protein (4 kcal/g) — the priority

Protein builds and preserves muscle, has the highest thermic effect (you burn 20–30% of its calories just digesting it), and is the most filling macro per calorie. In a deficit, adequate protein is the single biggest lever for keeping muscle while you lose fat. This is why every good macro calculator, including this one, sets protein first.

Fat (9 kcal/g) — the essential minimum

Dietary fat supports hormone production (including testosterone), vitamin absorption, and satiety. Going too low harms health and performance, so we hold fat to a floor of roughly 0.5 g per kg of bodyweight — usually 20–35% of calories.

Carbohydrates (4 kcal/g) — the flexible fuel

Carbs fuel hard training and brain function and are the most flexible macro. After protein and a fat minimum are covered, remaining calories go to carbs. More training generally means more carbs; less activity means you can run them lower without issue.

The protein-first method (and why we default to it)

The most trusted approach in evidence-based nutrition — used by coaches and the long-running IIFYM method — is protein-first:

1. Set protein from bodyweight and goal (higher in a cut).
2. Set fat to a healthy minimum (a percentage of calories, floored by bodyweight).
3. Fill the rest with carbs.

It works because it guarantees the two things that matter most — enough protein and enough fat — and treats carbs as the adjustable dial. The evidence for the protein range comes from reviews such as those summarised by the International Society of Sports Nutrition, which support roughly 1.6–2.2 g/kg for building and keeping muscle.

Preset splits: which one fits you?

Prefer fixed percentages? Our presets cover the common approaches:

• Balanced (30/40/30): a flexible, sustainable default for most people.
• High protein (40/35/25): best for cutting or building while training hard.
• Low carb (35/20/45): steadier energy for those who prefer fewer carbs.
• High carb (30/50/20): fuel for high-volume and endurance training.
• Keto (30/5/65): very low carb to stay in ketosis — precision matters here.

There is no single “best” split beyond hitting protein and a fat minimum. Choose the carb-to-fat ratio you enjoy and can stick to — adherence wins.

How to actually use your macros

1. Hit protein first, every day. If you only track one thing, track this.
2. Use per-meal targets. Splitting protein across 3–5 meals of ~0.4 g/kg each maximises muscle protein synthesis.
3. Weigh food for two weeks to calibrate. Then lean on hand portions when eating out or simplifying.
4. Adjust weekly, not daily. Judge progress on your weekly average weight and the mirror, not one day of tracking.

Common macro mistakes

Chronically under-eating protein

The most common and most costly error, especially in a deficit. Muscle is the price.

Fat too low for too long

Kills energy, mood, and hormones. Respect the fat floor.

Obsessing over perfection

Within 5–10 g on protein and close on calories is a win. Flexibility is what makes this last.

Forgetting to recalculate

As your weight and calories change, so do your macros. Re-run this calculator whenever your calorie target changes.

What to expect

Nail protein and your calorie target consistently and you will notice better fullness, steadier energy, and — over 4–8 weeks — visible changes in how you look, even at the same scale weight. Body composition is a slow game; the men who win it are the ones who keep showing up. That is the same philosophy behind our free 3-day plan and every article on the blog.