Macro calculator
Protein and carbohydrate each supply about 4 kcal per gram; fat supplies 9. That is why a high-fat split produces a much smaller number of grams for the same calories, and why fat is so easy to under-count: a tablespoon of oil is 120 kcal and takes up almost no room on a plate.
A starting point, not a prescription. Anyone with a medical condition, or who is pregnant or breastfeeding, should take dietary advice from a doctor or registered dietitian rather than a calculator.
Macros divide a calorie target into protein, carbohydrate and fat at 4, 4 and 9 kcal per gram. A 2,400 kcal target on a 30/40/30 split is 180 g protein, 240 g carbohydrate and 80 g fat. The panel builds the target first, from Mifflin–St Jeor and an activity factor, then applies the split you choose to it.
How to set your macros
A percentage split and a gram target are not the same instruction, and the difference shows up on protein. Only protein has an evidence-based figure per kilogram of bodyweight: the International Society of Sports Nutrition puts 1.4 to 2.0 g/kg/day as sufficient for most exercising people, and a meta-analysis of 49 trials covering 1,863 participants found that supplementing beyond a total intake of about 1.6 g/kg/day added nothing further to fat-free mass gains from resistance training. A percentage cannot know your bodyweight, so whether a split clears that floor depends entirely on how large the calorie target is.
Run the panel defaults through the four splits and the problem is visible. On a 1,686 kcal target for a 75 kg person, balanced at 30% gives 126 g of protein, or 1.69 g/kg, which clears the floor. Low carb at 35% gives 148 g, or 1.97 g/kg. Keto at 25% and high carb at 25% both give 105 g, which is 1.41 g/kg and lands below it. The same percentage on a 3,000 kcal target would be fine. This is the practical case for setting protein in grams and letting the percentages fall out, rather than the reverse.
The ratio between carbohydrate and fat is a much smaller question than the internet suggests. In the DIETFITS trial, 609 overweight adults were randomised to a healthy low-fat or a healthy low-carbohydrate diet for twelve months with no calorie target, and the two groups lost statistically indistinguishable amounts of weight. Genotype pattern and baseline insulin secretion did not predict who did better on which. Choose the split you can keep to for a year, because that is the variable the trial actually found.
One row on the panel is a different kind of number. The fibre target is 14 g per 1,000 kcal, which is the US Dietary Reference Intake convention rather than anything derived from your measurements, so it scales with the calorie target and with nothing else.
What people use it for
- Setting up a food tracking app
- Planning meals against a calorie target
- Comparing a keto split against a balanced one at the same calories
- Checking whether a percentage split clears your protein floor
- Converting a coach's gram targets back into percentages
- Seeing how many grams a change of split actually moves
Questions
Macronutrients: protein, carbohydrate and fat. They supply about 4, 4 and 9 kcal per gram, the Atwater factors, which are averages across food types rather than exact constants for any one food.
For most people 30/40/30 protein, carbohydrate and fat is a reasonable default. The split matters far less than the calorie total and the protein figure.
The position stands land at 1.4 to 2.0 g per kg of bodyweight for people training, and a large meta-analysis put the point of diminishing returns at about 1.6 g/kg/day.
Because 25% of a calorie target is less than 30% of the same target. At the panel defaults that is 105 g against 126 g, which is 1.41 versus 1.69 g per kg. Percentage splits do not know your bodyweight.
Not inherently. The DIETFITS trial randomised 609 adults to low-fat or low-carbohydrate eating for a year and found no significant difference in weight lost. Keto suits some people because it blunts appetite, which is an adherence effect rather than a metabolic one.
No. Within about ten grams is fine, and consistency across a week beats precision on any single day.
Because it carries more than twice the energy per gram. It also takes up very little room on a plate: a tablespoon of oil is around 120 kcal, which is why fat is the macro most often under-counted.
A flat 14 g per 1,000 kcal, the US Dietary Reference Intake convention. It is a dietary guideline scaled to your calorie target, not a result computed from your measurements.
Bodyweight is what the position stands are written in, and it is what this panel uses. Lean mass is arguably the better basis at high body fat percentages, where bodyweight overstates the tissue that actually needs feeding.
No. The target is computed first and the split only divides it. Switching from balanced to keto moves the grams around and leaves the total exactly where it was.