What this calculator does
Macronutrients supply energy at different rates: protein and carbohydrate provide about 4 kilocalories per gram, fat about 9. Splitting a calorie target between them converts percentages into the grams you would actually track.
There is no single correct split. Protein intake has the strongest evidence behind it, particularly for preserving muscle during weight loss and supporting training adaptation. The division of the remainder between carbohydrate and fat is largely a matter of preference, activity type and what you can actually sustain.
The formula
Each percentage is applied to the calorie total, then divided by that macronutrient’s energy density: 4 kcal per gram for protein and carbohydrate, 9 for fat. The protein-per-kilogram figure is included because that is the basis most sports nutrition guidance uses.
| Term | Meaning |
|---|---|
| Protein | 4 kcal per gram. Supports muscle repair and satiety. |
| Carbohydrate | 4 kcal per gram. The primary fuel for higher-intensity activity. |
| Fat | 9 kcal per gram. Required for hormone production and nutrient absorption. |
| g/kg | Grams of protein per kilogram of body weight: the standard basis for protein guidance. |
The inputs explained
| Field | What to enter |
|---|---|
| Daily calories (kcal) | Your daily calorie target. The TDEE calculator gives this figure. |
| Protein (%) | Percentage of calories from protein. |
| Carbohydrate (%) | Percentage from carbohydrate. |
| Fat (%) | Percentage from fat. The three should sum to 100: the calculator flags it if they do not. |
| Body weight (kg) | Body weight in kilograms, used only to express protein per kilogram. |
When to use it
Setting up a tracking target
Convert your calorie goal into grams so you have something concrete to track. Most people find protein the hardest to hit and benefit from planning it first.
Adjusting protein for training
Common guidance for people training regularly sits around 1.6 to 2.2 g per kilogram. Adjust the protein percentage until the per-kilogram figure lands in that band.
Comparing higher-carb and higher-fat approaches
Hold protein steady and shift the balance between the other two. Endurance training generally favours more carbohydrate; beyond that, the evidence for one split over another is weak and preference should decide.
Checking whether a plan is realistic
Very high protein percentages produce gram targets that are difficult to eat consistently. Seeing the grams rather than the percentage makes that obvious before you commit to a plan.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Macros at different calorie targets
A balanced split applied to a range of calorie targets.
| Daily calories | Protein | Carbohydrate | Fat | Protein per kg body weight |
|---|---|---|---|---|
| 1,600 kcal | 120 g/day | 160 g/day | 53 g/day | 1.60 g/kg |
| 1,800 kcal | 135 g/day | 180 g/day | 60 g/day | 1.80 g/kg |
| 2,000 kcal | 150 g/day | 200 g/day | 67 g/day | 2.00 g/kg |
| 2,200 kcal | 165 g/day | 220 g/day | 73 g/day | 2.20 g/kg |
| 2,600 kcal | 195 g/day | 260 g/day | 87 g/day | 2.60 g/kg |
| 3,000 kcal | 225 g/day | 300 g/day | 100 g/day | 3.00 g/kg |
How the protein percentage changes the grams
A fixed 2,200 kcal target with the protein share varying and the remainder split between carbohydrate and fat.
| Protein share | Protein | Protein per kg body weight | Percentages total |
|---|---|---|---|
| 15% | 83 g/day | 1.10 g/kg | 85.0%: adjust to 100% |
| 20% | 110 g/day | 1.47 g/kg | 90.0%: adjust to 100% |
| 25% | 138 g/day | 1.83 g/kg | 95.0%: adjust to 100% |
| 30% | 165 g/day | 2.20 g/kg | 100.0% ✓ |
| 35% | 193 g/day | 2.57 g/kg | 105.0%: adjust to 100% |
| 40% | 220 g/day | 2.93 g/kg | 110.0%: adjust to 100% |
Questions
What is a good macro split?
There is no single answer. A common general-purpose starting point is roughly 25 to 30 per cent protein with the remainder divided between carbohydrate and fat according to preference and activity. Protein has the strongest supporting evidence; the rest is far more flexible than most plans imply.
How much protein do I need?
General health guidance sits around 0.8 g per kilogram. People training regularly, or eating in a deficit while trying to preserve muscle, commonly aim for 1.6 to 2.2 g per kilogram. Individual needs vary and a dietitian can advise properly.
Why is fat 9 calories per gram?
Fat molecules are more reduced than carbohydrate or protein, so oxidising them releases more energy. That density is why fat percentage translates into fewer grams than the same percentage of carbohydrate.
Do my percentages have to add to 100?
Yes, for the calculation to represent your full intake. The calculator shows the total and flags it when the three do not sum correctly.
Does the split matter more than total calories?
For weight change, total energy is the dominant factor. Macronutrient distribution matters more for body composition, training performance and how satisfied you feel: which in turn affects whether you can sustain the intake at all.
To find your calorie target first, use the TDEE calculator. For timelines, see the weight change calculator.