Macro Calculator
Split your calories into protein, carbs and fat.
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Once you know your calorie target, macronutrients tell you what those calories should be made of. This calculator splits your daily calories into grams of protein, carbohydrate, and fat for several common diet styles.
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Macros — The Quick Answer
Protein and carbs provide 4 kcal per gram; fat provides 9. Divide your calories by the chosen percentages, then by the calorie-per-gram value to get grams.
Shortcut
grams = (calories × % of macro) ÷ (4 for protein/carbs, 9 for fat)
Common macro splits (P/C/F %)
| Diet | Protein | Carbs | Fat |
|---|---|---|---|
| Balanced | 30% | 40% | 30% |
| Low carb | 35% | 25% | 40% |
| High carb / endurance | 25% | 55% | 20% |
| Keto | 25% | 5% | 70% |
| High protein | 40% | 35% | 25% |
Fat is the most calorie-dense macronutrient at 9 kcal per gram, more than twice protein or carbohydrate — which is why high-fat diets reach their calories with smaller portions.
How It Works
The Formulas
Calories to grams
Formula
Protein (g) = (calories × protein%) ÷ 4 Carbs (g) = (calories × carb%) ÷ 4 Fat (g) = (calories × fat%) ÷ 9
Variables
Daily calorie target
Your total daily intake — from TDEE for maintenance, or adjusted for your goal.
Macro split
How your calories divide between the three macros. The three always sum to 100%.
Calories per gram
Protein and carbohydrate each give 4 kcal/g; fat gives 9 kcal/g.
Note: The 4-4-9 values are the Atwater factors, standard energy conversions used on nutrition labels worldwide.
Worked Example: 2,000 kcal on a Balanced Split
30% protein / 40% carbs / 30% fat
Split the calories by percentage
Protein 2,000 × 0.30 = 600 kcal; carbs 800 kcal; fat 600 kcal
Protein and carbs ÷ 4 kcal/g
600 ÷ 4 = 150 g protein; 800 ÷ 4 = 200 g carbs
Fat ÷ 9 kcal/g
600 ÷ 9 ≈ 67 g fat
Your daily macro targets
150 g protein, 200 g carbs, 67 g fat
Reference Guide
| Diet split (P/C/F) | Protein | Carbs | Fat |
|---|---|---|---|
| Balanced (30/40/30) | 150 g | 200 g | 67 g |
| Low carb (35/25/40) | 175 g | 125 g | 89 g |
| High protein (40/35/25) | 200 g | 175 g | 56 g |
| Keto (25/5/70) | 125 g | 25 g | 156 g |
Which Macro Split Is Right for You?
Why ratios matter even at the same calories
Protein is the macro most worth getting right — it preserves muscle and keeps you full. A balanced 30/40/30 is a solid default; whatever split you choose, make sure protein lands around 1.6–2.2 g per kg if you're training.
Best for: A sensible starting split for most people
Endurance athletes tend to favour more carbs for fuel; low-carb and keto diets push fat up and carbs very low. Neither is universally 'better' — carbs fuel hard training, fat supports hormones. Shift the dial to what suits your sport and tastes.
Best for: Tailoring the split to how you train and eat
Calories drive weight change; macros shape what that change is made of and how sustainable it feels. A 'perfect' ratio you abandon in a week loses to a good-enough one you keep for months. This is general nutrition information, not dietary advice.
Best for: Choosing a split you can maintain
What Are Macros?
Macros — macronutrients — are the three nutrients that supply all your calories: protein, carbohydrate, and fat. Counting macros means tracking grams of each rather than calories alone, because the balance between them affects muscle retention, hunger, and energy even at identical calories. The conversion is fixed: protein and carbohydrate each provide about 4 calories per gram, while fat provides about 9. This calculator takes your calorie target, applies a chosen split, and converts it into gram targets. You don't need to count macros to be healthy — it's a tool for specific goals like building muscle or hitting a protein target — but it gives a far richer picture than calories on their own.
Key Features
💡 Pro Tips
- →Set protein first (around 1.6–2.2 g/kg if training), then divide the remaining calories between carbs and fat to taste.
- →Get your calorie target from a TDEE calculation before splitting it — macros are a slice of a total, so the total has to be right first.
- →Prioritise whole-food sources within each macro; 150 g of protein from varied whole foods beats the same grams from shakes alone.
- →Don't obsess over hitting macros to the gram — being consistently close is what matters.
Common Mistakes
Chasing a split without setting calories first
Macros are percentages of a calorie total. If the total is wrong, perfect ratios still won't produce the result you want. Fix calories (TDEE) first, then split.
Neglecting protein
Protein is the macro most linked to muscle retention and fullness. Splits that leave protein too low make fat loss harder and risk losing muscle.
Treating one split as magic
At equal calories, no split uniquely melts fat. Carbs vs fat is largely preference and training-driven; adherence matters more than the exact ratio.
Research & Citations
Sources and standards referenced for the factual claims on this page
- [1]
Atwater, W. O. (1900). The energy value of food (origin of the 4-4-9 calorie factors). US Department of Agriculture.
Source of the calories-per-gram values for each macronutrient.
View source - [2]
Jäger, R., et al. (International Society of Sports Nutrition) (2017). ISSN Position Stand: Protein and Exercise. Journal of the International Society of Sports Nutrition, 14.
Evidence base for protein targets within a macro split.
View source - [3]
Academy of Nutrition and Dietetics (2023). Acceptable Macronutrient Distribution Ranges. eatright.org.
Guidance on sensible macronutrient distribution.
View source
This calculator is a reference tool, not a substitute for professional advice. Verify important health, financial, legal, or safety decisions with a suitably qualified professional.
Last updated: October 7, 2026
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Frequently Asked Questions
How do I calculate my macros?
Start with your daily calories, apply the split percentages, then divide: protein and carb grams use 4 kcal/g, fat uses 9 kcal/g. For 2,000 kcal at 30/40/30, that's 150 g protein, 200 g carbs, and 67 g fat.
What's a good macro split?
For general health, a balanced 30/40/30 works well. Endurance athletes often favour more carbs, people doing keto use very low carbs and high fat, and anyone building muscle may want protein around 30–40%. The best split is one you can stick to.
How much protein do I need per day?
General guidance is about 0.8 g per kg of body weight for sedentary adults, rising to 1.6–2.2 g/kg for those training to build muscle. This calculator's protein percentage gives an alternative way to hit a suitable figure.
Why is fat 9 calories per gram?
Fat molecules store more chemical energy per gram than carbohydrates or protein, so they yield about 9 kcal/g versus 4. This is a fixed property of the nutrients, not a diet choice.