Macro Calculator
Protein, carbs, and fat grams from calories and split percents.
What it does
Calories set body weight direction while macros shape composition and performance. Protein builds and protects muscle, carbs fuel training, and fat carries hormones and satiety. Splitting calories by percent converts the plan into grocery grams.
The tool above takes daily calories with protein, carb, and fat shares. It returns each in grams, rejecting splits that miss one hundred percent.
Protein leads every serious split because requirements scale with body weight and training, not with appetite. Carbs flex most with training volume, rising on hard days and falling on rest ones.
Fat floors matter. Diets below about 15% fat risk hormone and vitamin issues, which is why low fat extremes suit almost nobody long term.
How to use
- Enter the daily calorie target from the calorie calculator.
- Set protein share first, usually 25 to 35%.
- Split the rest between carbs and fat.
- Check the three add to 100, then shop the grams.
Formula
- 4 kcal/g
- Energy in protein and carbohydrate.
- 9 kcal/g
- Energy in fat, more than double.
- 100%
- Shares must total the whole calorie budget.
Fiber counts inside carbs on labels but yields little energy. Net carbs subtract fiber for low carb tracking.
Worked example
Example: 2500 kcal at 30/40/30
Calories 2500, protein 30%, carbs 40%, fat 30%.
- Protein: 2500 x 0.30 / 4 = 187.5, shown as 188 g.
- Carbs: 2500 x 0.40 / 4 = 250 g.
- Fat: 2500 x 0.30 / 9 = 83.33, shown as 83 g.
- Check energy: 188x4 + 250x4 + 83x9 = 752 + 1000 + 747 = 2499, rounding to target.
Reference table
| Goal | Split | At 2500 kcal |
|---|---|---|
| Balanced | 30/40/30 | 188 / 250 / 83 g |
| Muscle gain | 30/50/20 | 188 / 313 / 56 g |
| Low carb | 35/15/50 | 219 / 94 / 139 g |
| Endurance | 20/55/25 | 125 / 344 / 69 g |
Limits
- Energy math only. Food quality sits outside grams.
- Fiber, alcohol, and sugar alcohols complicate labels.
- Individual protein needs vary with size and training.
- Medical diets need clinician splits, not templates.
Common mistakes
- Setting macros before calories, then wondering at stalls.
- Dropping fat under 15% for months.
- Counting percentages that add to 97 or 103.
- Ignoring liquid calories in the split.
- Copying athlete splits at half the training.
Try it yourself
Quick checks. Answers sit tucked under each question.
2000 kcal at 40/40/20?
Protein 200 g, carbs 200 g, fat 44 g (400/9 = 44.44).
Grams check for that split?
800 + 800 + 400 = 2000 kcal. Matches.
Questions
What split builds muscle?
Near 30/50/20 at a small surplus: high protein, training fueled, moderate fat.
How much protein per day?
Pair this page with the protein calculator: 1.2 to 2.2 g per kg by goal.
Do I need to hit exact grams?
Near matters. Calories within five percent and protein within ten grams rule outcomes.
What about fiber?
Aim 25 to 35 g daily inside carb grams. Vegetables and legumes carry it.
Is fat bad for loss?
No. Keep 20 to 35% for hormones and fullness while calories run the deficit.
Should rest days differ?
Slightly fewer carbs works for many. Protein stays constant daily.