Macro calculator
Split a day's calories into carbohydrate, protein and fat in grams — with protein per kilogram if you enter weight.
The arithmetic is one division: multiply calories by the share, divide by the energy per gram (4, 4 and 9 kcal). The hard part is choosing the split, and there is no single right answer, so a few common ones are provided and every field stays editable. Take the daily calorie figure from the BMR and TDEE calculator.
Calories and split
What you enter is saved in this browser, so it is still here next time
Take this from the BMR and TDEE calculator.
50 / 20 / 30 — a reasonable default.
Enter it to see protein per kilogram. Zero skips it.
Per day
Daily calories
2,200 kcal
Protein per kg
1.57 g/kg
Grams by macronutrient
| Macro | Share | Calories | Grams |
|---|---|---|---|
| Carbohydrate | 50% | 1,100 kcal | 275 g |
| Protein | 20% | 440 kcal | 110 g |
| Fat | 30% | 660 kcal | 73.3 g |
Energy per gram is 4, 4 and 9 kcal. These are the Atwater factors, the same basis used on nutrition labels.
Arithmetic on a calorie figure. What suits an individual depends on health, medication and activity. Not medical advice.
Calories × share ÷ energy per gram
Splitting 2,200 kcal a day into 50·20·30 gives 1,100 kcal of carbohydrate, 440 of protein and 660 of fat. Dividing by 4, 4 and 9 gives 275 g, 110 g and 73.3 g. The table lists the three rows as share, calories and grams, with grams to one decimal place. Fat has 4/9 the grams of carbohydrate for the same calories, so 660 kcal coming to only 73 g is not an error.
Four presets, and editing by hand
Balanced 50·20·30, high-protein 40·30·30, low-carb 25·35·40 and keto 5·25·70 are provided. At 2,200 kcal the protein is 110 g, 165 g, 192.5 g and 137.5 g respectively, and keto's carbohydrate is 27.5 g. Edit the three fields and the calculation follows your numbers; if the edited shares match a preset, the selector points at it. If they match none, the selector stays on the first preset while the arithmetic still uses what you entered.
Enter a weight and protein per kilogram appears
It is protein grams divided by body weight: 110 g at 70 kg is 1.57 g/kg. It is handy for working backwards — hitting 1.6 g/kg needs 112 g, or 448 kcal, which is 20.4% of 2,200 kcal; 2.0 g/kg needs 140 g, 560 kcal, 25.5%. A percentage alone hides that number, which is why it has its own line. With weight at 0 the line does not appear.
When the shares do not total 100, and what is left out
If the three shares do not add to 100 the page says so and calculates anyway. At 50·30·30 the total is 110%, and the calories implied by the grams come to 2,420 kcal, not the figure you entered. Silently normalising would hide which field is wrong. The daily calorie figure itself is not computed here, fibre, sugars and alcohol are not separated, and nothing is split by meal. There is no correct split, and this page does not choose one.
Common questions
QWhere do 4, 4 and 9 kcal per gram come from?
They are the Atwater factors, worked out in the early twentieth century and still used on nutrition labels. Energy actually absorbed varies a little by food, but using the same basis as the label is what makes your arithmetic agree with the packet. Alcohol is 7 kcal per gram; this screen does not handle it.
QHow much protein per day?
The recommended intake is 0.8 g per kilogram, but that is the floor for avoiding deficiency. For building muscle while training, or protecting it during a deficit, 1.6–2.2 g/kg is commonly cited. Protein per kilogram is shown alongside the percentages because a percentage alone hides that number.
QWhat if the shares do not add to 100%?
The screen says so and calculates anyway. Silently normalising would hide which field is wrong. When the total is not 100%, the calories implied by the grams will not match the daily figure you entered either.
QHow many grams is 30% protein on 1,800 kcal?
1,800 × 0.3 = 540 kcal, divided by 4 is 135 g. At 60 kg that is 2.25 g/kg. Set the calories to 1,800 and protein to 30 and the table shows exactly that.
QWhy are the fat grams so low?
At 9 kcal per gram, the same calories come to 4/9 of the grams of carbohydrate or protein. 30%, or 660 kcal, is 73.3 g of fat; the same 660 kcal as carbohydrate would be 165 g. Compare it directly with the fat grams on a food label — a small number does not mean a small share.