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Energy & Nutrition

Macro Calculator

Split your daily calories into protein, carbs, and fat — across five plans, or build your own.

Formula: Calorie target × macro splitReviewed for accuracy on Mon, Aug 10, 2026
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Count training sessions rather than judging yourself — most people pick one level too high.

Your goal

Mifflin-St Jeor is the best-validated for most people.

Your split
Plan
Enter your details to see your result.

Key takeaways

  • For weight change, total calories dominate. Two large randomised trials found no meaningful difference between macro splits at matched calories.12
  • Protein is the exception — it is the one macro where the amount genuinely changes body composition rather than just the numbers.4
  • Set protein first, set a fat floor (roughly 0.5–0.8 g/kg), and let carbohydrate take whatever is left.
  • The IOM's acceptable ranges are wide on purpose: 45–65% carbohydrate, 20–35% fat, 10–35% protein.3
  • Pick the split you can actually eat. Adherence is what separates diets that work from diets that don't.

Understanding your result

Macros convert your calorie target into grams. Protein and carbohydrate provide 4 kcal per gram; fat provides 9, which is why the fat number looks small next to the others.

Each figure is shown beside the Institute of Medicine's Acceptable Macronutrient Distribution Range for that nutrient, so you can see how much room there actually is: 10–35% for protein, 45–65% for carbohydrate, 20–35% for fat.

Two of the plans sit deliberately outside those ranges. Low Carb and Keto are established approaches rather than points on the published range, and the calculator says so rather than quietly implying they are equivalent.

What the trials actually found

This is one of the most thoroughly tested questions in nutrition, and the answer disappoints people who want it to be more interesting.

Sacks and colleagues randomised 811 overweight adults to four diets spanning very different fat, protein and carbohydrate ratios, matched on calories, and followed them for two years. Weight loss was essentially the same across all four.1 Nearly a decade later, DIETFITS randomised 609 adults to healthy low-fat or healthy low-carbohydrate diets for twelve months — this time without calorie targets, and with genotype and insulin-secretion patterns tested as predictors of which diet would suit whom. Average weight loss differed by about a kilogram, which was not statistically significant, and neither genotype nor insulin status predicted who did better on which.2

  • Healthy low-fat5.3 kg lost
  • Healthy low-carb6 kg lost
Twelve-month weight loss, low-fat vs low-carb (DIETFITS, 2018). 609 adults, no calorie targets, twelve months. The difference was not significant.
Twelve-month weight loss, low-fat vs low-carb (DIETFITS, 2018)
MethodValue (kg lost)
Healthy low-fat5.3
Healthy low-carb6

What this does and does not mean

It does not mean macros are irrelevant — they change satiety, training performance, blood lipids and how easy a diet is to stick to. It means that if two people eat the same calories and the same protein, the carb-to-fat ratio is not what decides how much weight they lose.

Setting the three numbers in order

Because the evidence points that way, there is a sensible order of operations: fix the thing that matters, protect the thing that has a floor, and let the third absorb the remainder.

  1. Protein first. Roughly 1.6 g/kg for building, up to 2.2–2.4 g/kg in a deficit. This is the one macro with a body-composition effect independent of calories.4 The Protein Calculator sets it properly.
  2. Fat second, as a floor rather than a target. Below about 0.5 g/kg, fat-soluble vitamin absorption and hormone production start to suffer — a meta-analysis found low-fat diets associated with meaningfully lower testosterone in men.5 Set 0.5–0.8 g/kg and go above it freely if you prefer.
  3. Carbohydrate last. Whatever calories remain. Carbohydrate is the most useful fuel for hard training and the easiest macro to flex, which makes it the natural remainder.
Common splits and who each one actually suits.
SplitProtein / Carb / FatSuits
Balanced30 / 40 / 30Most people, most of the time. A sensible default.
Higher-carb25 / 55 / 20Endurance athletes and anyone training hard most days.
Lower-carb35 / 25 / 40People who find carbohydrate poorly satiating, or manage blood glucose.
Ketogenic25 / 5 / 70A specific therapeutic tool. Restrictive, and no better for weight loss at matched calories.

Where the ratio does matter

Having said the ratio does not drive weight loss, there are places it clearly matters — and knowing which is which is the point of understanding this rather than just following a template.

  • Training performance. Glycogen fuels high-intensity work. Cut carbohydrate hard and hard sessions will feel worse, which over months means less training stimulus.
  • Satiety. Highly individual and worth taking seriously. Some people find fat filling and carbohydrate not; for others it is the reverse. Whichever is true of you is the diet you should be on.
  • Blood glucose management. For people with insulin resistance or type 2 diabetes, carbohydrate quantity and quality have direct clinical relevance beyond weight.
  • Blood lipids. Different splits move LDL, HDL and triglycerides in different directions. If yours are a concern, this is a conversation to have with a doctor rather than a calculator.
  • Very low fat. Sustained below roughly 20% of calories, there are real costs to hormone production and fat-soluble vitamin absorption.5

Precision beyond your measurement error is theatre

Hitting 30/40/30 exactly is not meaningfully better than landing within five points of it, and food labels alone carry an error margin of up to 20%. Get protein close, keep fat above the floor, and stop optimising the last few grams.

How the plans compare

The five plans are five points on the same axis. Seeing them side by side makes clear how much — and how little — separates them, and which two step outside the published ranges altogether.

The five plans, as a share of calories.
PlanProteinCarbsFatInside every AMDR?
Balanced30%40%30%Yes (success)
Low Fat25%55%20%Yes (success)
Low Carb35%25%40%No — carbs below 45% (warning)
High Protein40%35%25%Yes (success)
Keto25%5%70%No — well outside (danger)

What the numbers look like as food

Gram targets are abstract until you can see them on a plate. The table below is the same dataset the carbohydrate, fat and protein calculators use, so the figures agree across all four pages.

Macronutrients in common foods, per serving.
FoodServingProtein (g)Carbs (g)Fat (g)
Protein foods
Chicken breast, cooked100 g3103.6
Beef mince, cooked100 g26015
Pork loin, cooked100 g27.9014.6
Salmon, cooked100 g25.4012.4
Shrimp, cooked100 g24.10.20.3
Egg1 large (50 g)6.30.45
Tofu, firm100 g17.32.89
Lentils, cooked1 cup (198 g)17.939.90.8
Black beans, cooked1 cup (172 g)15.240.80.9
Greek yogurt, plain 0%170 g17.36.10.4
Grains and starches
Rice, white, cooked1 cup (158 g)4.244.10.4
Rice, brown, cooked1 cup (195 g)5.545.81.8
Oats, dry40 g5.3272.8
Pasta, cooked1 cup (140 g)8.143.21.3
Bread, wholemeal1 slice (32 g)414.31.1
Potato, baked with skin1 medium (173 g)4.3370.2
Sweet potato, baked1 medium (114 g)223.60.1
Quinoa, cooked1 cup (185 g)8.139.43.6
Fruit and vegetables
Apple1 medium (182 g)0.525.10.3
Banana1 medium (118 g)1.3270.4
Orange1 medium (131 g)1.215.40.2
Strawberries1 cup (152 g)111.70.5
Broccoli, cooked1 cup (156 g)3.711.20.6
Spinach, raw1 cup (30 g)0.91.10.1
Carrots, raw1 cup (128 g)1.212.30.3
Avocado1/2 (100 g)28.514.7
Fats, nuts and oils
Olive oil1 tbsp (13.5 g)0013.5
Butter1 tbsp (14 g)0.1011.5
Almonds28 g (about 23)66.114
Walnuts28 g4.33.918.5
Peanut butter2 tbsp (32 g)7.27.116.4
Cheddar cheese28 g6.60.59.3
Chia seeds28 g4.7128.6
Drinks and sweets
Milk, whole1 cup (244 g)7.911.78
Orange juice1 cup (248 g)1.725.80.5
Cola1 can (355 mL)0390
Beer, regular1 can (355 mL)1.612.60
Dark chocolate, 70%28 g2.212.812.1

The useful habit this builds is estimation, not tracking. Once you know a chicken breast is roughly 30 g of protein and a cup of rice roughly 45 g of carbohydrate, you can construct a day that lands close to your targets without weighing anything.

Terms used on this page

Macronutrients
Protein, carbohydrate and fat — the three components of food that supply energy. Protein and carbohydrate provide about 4 kcal per gram, fat about 9.
AMDR
Acceptable Macronutrient Distribution Range — the IOM's evidence-based ranges associated with reduced chronic disease risk while meeting nutrient needs. Deliberately wide.
Glycogen
Carbohydrate stored in muscle and liver, and the main fuel for high-intensity exercise. Each gram is stored with around 3 g of water, which is why cutting carbohydrate produces fast early scale weight loss that is not fat.
Ketogenic diet
Carbohydrate low enough (typically under 50 g/day) to shift the body toward ketones for fuel. An effective tool for some people, and not superior for weight loss when calories and protein are matched.

The formula

Grams from %
protein g = (calories × %) / 4; carbs g = (calories × %) / 4; fat g = (calories × %) / 9
Plans (protein / carbs / fat)
Balanced 30/40/30 · Low Fat 25/55/20 · Low Carb 35/25/40 · High Protein 40/35/25 · Keto 25/5/70
Create your own
moving one macro redistributes the change across the other two in proportion to their current shares; each stays ≥ 5%
Worked example
  1. 2,000 kcal, Balanced (30P/40C/30F)
  2. Protein = 600/4 = 150 g
  3. Carbs = 800/4 = 200 g
  4. Fat = 600/9 ≈ 67 g
Result: 150P / 200C / 67F

Source: Calorie target × macro split. Published clinical/scientific formula.

Limitations

  • Macro splits are a starting point, not a prescription — adjust based on results and preference.
  • Keto's 5% carb limit is strict, sits far outside the published ranges, and is not suitable for everyone.
  • The custom sliders will happily build a split outside every AMDR. That is intentional — but the ranges shown beside each figure are how you tell when you have left them.
  • No macronutrient can be dragged below 5% of calories. A split with none of something is not a plan this calculator will help you build.
  • Grams are rounded to whole numbers, so the three macros can multiply back to a calorie total a few kcal from the headline.

References

Not medical advice. This calculator is for general informational purposes only and is not a substitute for professional medical guidance. Always consult a qualified healthcare provider before making decisions about your health. Read the full medical disclaimer.

Reviewed for accuracy on Mon, Aug 10, 2026