Macro Split Calculator
Macro splits are quoted as percentages of calories but eaten in grams, and the conversion is not symmetrical: protein and carbohydrate are four calories a gram while fat is nine. That means a percentage point of fat buys noticeably fewer grams than a percentage point of carbohydrate. This does the conversion, then multiplies the grams back out to show exactly how close whole grams get to the target.
What this generator does
Divides each macro's share of the calorie target by its calories per gram — four for protein and carbohydrate, nine for fat — and rounds to whole grams. It then multiplies the grams back out and compares the total against the target.
How to use this tool
- Enter your daily calorie target.
- Set the protein and carbohydrate percentages; fat takes the rest.
- Read the grams of each.
- Check the total: whole grams cannot always hit a target exactly.
Understanding the controls
- Daily calories
- The target the grams have to reconcile against.
- Protein percentage
- Four calories a gram. Higher protein splits are common when the aim is to keep muscle while eating less.
- Carbohydrate percentage
- Also four calories a gram. Fat takes whatever is left of the hundred, which the page states before you run it.
Common use cases
- Converting a percentage macro split into daily gram targets
- Comparing two splits by grams rather than by percentages
- Teaching the four-four-nine rule with a worked conversion
- Setting up a food diary with gram targets
- Seeing how much a percentage change actually moves each macro
How this generator works
Each macro's calorie share is its percentage of the target, and its grams are that divided by its calories per gram. Rounding to whole grams means the total rarely lands exactly on the target, so the tool multiplies the grams back out and reports what they actually come to — a difference of a few calories is rounding, and saying so is more useful than quietly adjusting a figure to make the sum look tidy.
Randomness and fairness
Nothing here is random. A calorie target and a split give exactly one set of grams.
For how randomness is produced across the whole site, see how Generate Random works.
Limitations and good to know
- The four-four-nine rule is a convention that rounds the true energy values, and fibre in particular contributes less than four.
- This converts a target into grams; it does not decide what your target should be, which depends on far more than arithmetic.
- Alcohol is seven calories a gram and is not included in the split.
- Nothing here is nutritional or medical advice, and individual needs vary a great deal.
Privacy and your data
The conversion runs in your browser. Your calorie target and percentages are never transmitted, stored or included in analytics.
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