Macro Calculator
Protein, carbs & fat grams from your calories
Turn a calorie target into daily grams of protein, carbs and fat. Set your split (or use the balanced default) and get exact gram targets.
How macros convert to grams
An iifym calculator works the same way, since "if it fits your macros" is a percentage split turned into grams.
Each macronutrient carries a fixed energy value, so a percentage split converts straight into grams:
| Macro | Calories per gram | At 30% of 2,200 cal |
|---|---|---|
| Protein | 4 | 165 g |
| Carbohydrate | 4 | 165 g |
| Fat | 9 | 73 g |
Fat carries more than twice the energy per gram, which is why a 30% fat allocation looks so much smaller on the plate than a 30% protein one. The same percentage is a very different quantity of food.
General information, not dietary or medical advice. Individual needs vary, and anyone with a health condition or specific goal should speak to a clinician or registered dietitian.
Common splits at 2,200 calories
| Split (P/C/F) | Protein | Carbs | Fat | Protein per lb |
|---|---|---|---|---|
| 30/40/30 balanced | 165 g | 220 g | 73 g | 0.97 |
| 40/30/30 high protein | 220 g | 165 g | 73 g | 1.29 |
| 25/50/25 higher carb | 138 g | 275 g | 61 g | 0.81 |
| 30/20/50 low carb | 165 g | 110 g | 122 g | 0.97 |
| 25/5/70 ketogenic | 138 g | 28 g | 171 g | 0.81 |
Enter your body weight above and the calculator shows protein in grams per pound alongside the totals, which is the unit protein guidance is actually written in.
Set protein first
Percentage splits have an awkward property: at a fixed percentage, your protein target moves whenever your calories move. Cut from 2,500 to 1,800 calories at 30% protein and protein drops from 188 g to 135 g — exactly when preserving muscle matters most.
The common approach among people who train is to work the other way: fix protein in grams per pound of body weight, then let carbohydrate and fat absorb the remaining calories. Research generally supports roughly 0.7 to 1 g per pound for building or preserving muscle, with little further benefit above that.
| Body weight | Protein | As % of 2,000 cal | As % of 2,800 cal |
|---|---|---|---|
| 130 lb | 104 g | 21% | 15% |
| 150 lb | 120 g | 24% | 17% |
| 170 lb | 136 g | 27% | 19% |
| 200 lb | 160 g | 32% | 23% |
| 230 lb | 184 g | 37% | 26% |
Notice how the same absolute target is a completely different percentage depending on calories. That is the argument for setting grams rather than percentages, and for adjusting the percentage inputs above until the gram figure matches your target.
Make the percentages total 100
The three inputs are independent, so nothing stops them summing to 90 or 110 — and if they do, the grams no longer add up to the calories you entered. At 40/40/30 the split totals 110%, and those grams carry 2,420 calories rather than 2,200. The calculator flags this and shows what the grams actually total, but the fix is to adjust the inputs until they read 100%.
Choosing a split, honestly
Total calories and protein drive most outcomes. The carbohydrate-to-fat ratio matters far less than the internet suggests, and the best split is largely the one you can follow.
- Carbs fuel hard training. If sessions feel flat, more carbohydrate is usually the answer.
- Fat supports hormone production and satiety, and is generally not taken below about 20% of calories.
- Very low carbohydrate approaches work for some people and are difficult for others. Neither outcome indicates a metabolic advantage; adherence does most of the work.
- Fibre is not tracked here but matters. Most people fall well short of the 25 to 35 g commonly recommended.
- Close is enough. Landing within about 10 g most days over a week beats hitting exact numbers for three days and abandoning it.
Work out your calorie target first with the TDEE calculator, since macros are a division of that number rather than a substitute for it.
How this macro calculator works out its numbers
Grams are calories × percentage ÷ calories per gram, using 4 cal/g for protein and carbohydrate and 9 cal/g for fat. These are the Atwater general factors used on nutrition labels.
- The three percentages are independent inputs. If they do not total 100%, the resulting grams will not match your calorie target — the calculator says so and shows what they actually total.
- Protein per pound is shown when you enter body weight, since protein guidance is normally expressed that way rather than as a percentage.
- Alcohol is not modelled at 7 cal/g, and fibre is not tracked separately though it is counted within carbohydrate on US labels.
- Atwater factors are averages. Real absorbed energy varies by food and preparation, typically by a few percent.
- Not dietary advice. Splits described here are common conventions rather than recommendations, and individual needs differ.
Reviewed September 2026.
Figures reviewed . Every worked example on this page is checked against the calculator above.
Macro Calculator: frequently asked questions
How do I convert macros to grams?
Multiply calories by the percentage, then divide by 4 for protein and carbohydrate or 9 for fat. At 2,200 calories, 30% protein is 165 g while 30% fat is only 73 g, because fat carries more than twice the energy per gram.
What's a good macro split?
30/40/30 protein, carbs and fat is a reasonable balanced default. Higher protein splits like 40/30/30 suit muscle-building or fat loss. Total calories and protein drive most outcomes; the carb-to-fat ratio matters less than commonly claimed.
How much protein do I need?
Roughly 0.7 to 1 gram per pound of body weight for building or preserving muscle, with little further benefit above that. For a 170 lb person that is about 120 to 170 g a day.
Why should I set protein in grams rather than a percentage?
Because a fixed percentage moves your protein target whenever calories change. Cutting from 2,500 to 1,800 calories at 30% protein drops protein from 188 g to 135 g, exactly when preserving muscle matters most.
What if my macro percentages don't add to 100?
The grams will not match your calorie total. At 40/40/30 the split sums to 110% and those grams carry 2,420 calories rather than 2,200. The calculator flags it and shows the real total, but you should adjust the inputs to 100%.
How low can I take fat?
Fat is generally not reduced below about 20% of calories, since it supports hormone production and satiety. Very low fat intakes are hard to sustain and offer no particular advantage.
Does the carb to fat ratio really matter?
Much less than total calories and protein. Carbohydrate fuels hard training and fat supports satiety, so the practical answer is to shift toward whichever your training and appetite need. Adherence matters more than the ratio.
Do I need to hit my macros exactly?
No. Landing within about 10 grams most days across a week is more useful than exact precision for a few days followed by abandoning it. Protein is the one worth tracking most carefully.