Macro Calculator | FigureBetter

Your inputs

Calories, and how to divide them

Units

Daily calorie target

The number being divided up. Work it out first if you do not have one.

Split

Protein first, then carbs, then fat. Outside the protein column these are conventions, not findings.

Body weight

Used for the grams-per-kilogram readout, and for the protein floor below.

Protein floor

0 leaves the percentage in charge. 1.6 g/kg is a common figure for someone training through a deficit.

Meals a day

Count snacks. Meal timing has little effect on the day’s total; this is only here to make the numbers usable.

Your inputs are calculated locally and are not stored.

Protein · carbs · fat150 g · 200 g · 67 g

2,000 kcal a day split 30 / 40 / 30, which comes to 2.14 g of protein per kilogram of body weight. The percentage split set the protein figure.

Protein: 150 g · 600 kcal · 30%
Carbohydrate: 200 g · 800 kcal · 40%
Fat: 67 g · 600 kcal · 30%
Protein per kilogram: 2.14 g/kg of 70 kg
What set the protein figure: The percentage split
Calories per meal: 667 kcal across 3 meals

Grams a day and grams a meal, across 3 meals
Macro	Per day	Per meal	Calories
Protein	150 g	50 g	600 kcal
Carbohydrate	200 g	67 g	800 kcal
Fat	67 g	22 g	600 kcal

The 4 / 4 / 9 factors are averages over a mixed diet, not constants. Fibre is carbohydrate that yields nearer 2 kcal a gram, so a high-fibre day is over-counted here.
Alcohol is a fourth macronutrient at 7 kcal a gram and no split on this page accounts for it. A 300 kcal evening puts you 300 kcal over the target above, or forces the other three down.
Protein is the column worth being precise about — the evidence for satiety and for holding lean mass in a deficit is far stronger than anything separating one carb-to-fat ratio from another at the same calories.
Grams are the calorie share divided by the factor and then rounded, so multiplying them back can miss by a few calories. 67 g of fat is 603 kcal on the way back, against a share of 600. That is rounding, not a mistake.

Before you use the numbers

This is general information, not medical advice

This page divides one number by three percentages and explains where the conversion factors came from. It is general educational information, not medical or dietetic advice, and it knows nothing about you beyond a calorie figure and a body weight.

Talk to a doctor or a registered dietitian before making substantial changes, and especially before adopting a split far outside ordinary eating. That matters most if you have kidney or liver disease, diabetes, a lipid disorder, are pregnant or breastfeeding, are under 18, or have any history of disordered eating. Precise gram targets are a useful tool for some people and a harmful preoccupation for others; if tracking makes food worse rather than better, that is worth more attention than the numbers.

Formula & methodology

How the split is worked out

Each percentage claims a share of the calorie target, and each share is divided by that macronutrient’s energy density to get grams.

grams = (kcal × share) ÷ factor • factors: protein 4, carbohydrate 4, fat 9 • floor = kg × g/kg

share: The macronutrient’s percentage of the day, as a fraction
factor: The general Atwater factor — metabolisable energy per gram, averaged over a mixed diet
floor: Grams of protein per kilogram of body weight, applied as a minimum rather than a target

The four named splits are protein / carbohydrate / fat: balanced 30/40/30, low-carb 40/20/40, endurance 25/55/20, and keto 25/5/70. A custom split has to total exactly 100 — nothing here normalises a split you did not ask for, because handing back percentages you never typed is worse than refusing. The running total is shown beside the fields so the correction is obvious.

When a protein floor is set, both constraints are computed and the larger gram figure wins. If the floor wins, its extra calories come out of carbohydrate and fat in the split’s own ratio, so a keto plan stays keto-shaped and an endurance plan stays carbohydrate-leaning. The result names which constraint won, because quietly ignoring one of two inputs is the worst available option. Pounds are converted at exactly 0.45359237 kg before the floor is applied; the literature states protein per kilogram, so that is the unit the floor lives in.

Worked example

2,000 kcal, balanced — and then the same day on keto with a floor

Balanced is 30/40/30. Protein takes 30% of 2,000 = 600 kcal, and 600 ÷ 4 = 150 g. Carbohydrate takes 40% = 800 kcal, and 800 ÷ 4 = 200 g. Fat takes the same 30% = 600 kcal, but at 9 kcal a gram that is only 66.7 g, which prints as 67. Across three meals: 50 g of protein, 67 g of carbohydrate and 22 g of fat each, on about 667 kcal. For a 70 kg person, 150 g of protein is 2.14 g per kilogram — comfortably above any published floor, so the percentage is in charge.

Now switch the same 2,000 kcal to keto, 25/5/70, and set a floor of 2.2 g/kg. The percentage alone would give 25% × 2,000 ÷ 4 = 125 g of protein. The floor asks for 70 × 2.2 = 154 g. The floor is larger, so it wins, and protein takes 154 × 4 = 616 kcal. That leaves 1,384 kcal, which is split in keto’s own 5:70 ratio rather than evenly: carbohydrate gets 5/75 of it, about 92 kcal or 23 g, and fat gets the remaining 1,292 kcal, about 144 g. The split has been bent to satisfy the floor, and the result says so rather than pretending the percentages were honoured.

The honest part

Protein is the column worth arguing about

The three macronutrients do not have equally strong evidence behind them, and a calculator that presents them as three equal dials misrepresents the science. Protein is the one that earns its precision. It is the most satiating of the three per calorie, it carries the highest thermic cost to digest, and — the part that matters in a deficit — it is what preserves lean mass when energy is short. A 2018 meta-analysis of protein supplementation and resistance training put the point of diminishing returns at roughly 1.6 g per kilogram of body weight per day, with the confidence interval reaching about 2.2. That is a real number with real evidence under it, which is exactly why this page offers a grams-per-kilogram floor that can override the percentage.

The carbohydrate-to-fat ratio is a different matter. When trials hold calories constant and hold protein constant, the difference between a low-carbohydrate and a low-fat arm on fat loss is small and often not statistically distinguishable. The ratio still matters — to how full you feel, to how your training goes, to your blood lipids and blood glucose if either is a concern, and above all to whether you can keep it up past week six. But it is a question about adherence and preference far more than about metabolism. Anyone who tells you a specific carbohydrate percentage unlocks fat loss is selling something.

One consequence worth stating plainly: the presets here are conventions, not prescriptions. Balanced 30/40/30 is a round number that fits inside the Institute of Medicine’s acceptable ranges. Keto’s 25/5/70 sits well outside two of those three ranges. Neither is derived from a trial that found it optimal, because no such trial exists for the general population. Pick the one you will still be following in three months.

Where 4/4/9 is wrong

The conversion factors are averages

4 kcal per gram of protein, 4 per gram of carbohydrate and 9 per gram of fat are the general Atwater factors. They are averages over a mixed diet, derived over a century ago from heats of combustion adjusted for typical digestibility and typical urinary losses. They are good enough for a food label and not good enough to treat as physical constants. Three specific places they slip:

Fibre is not 4 kcal a gram. It is carbohydrate that human enzymes do not digest; what energy it yields comes from bacterial fermentation in the colon, and the usual working figure is about 2 kcal a gram. A day built on vegetables, legumes and whole grains carries meaningfully less energy than its carbohydrate column claims. Different jurisdictions handle this differently on labels, which is why the same food can carry two different calorie counts in two countries.
Alcohol is a fourth macronutrient at 7 kcal a gram, and no preset here has a column for it. Two glasses of wine is roughly 250 to 300 kcal that this page has not allocated. Either your day runs over the target, or those calories have to be taken out of the other three before you split. Subtract them from the calorie target first and plan the remainder — that is the only version of this arithmetic that stays true.
Protein rarely delivers its full 4.The thermic effect of protein is 20 to 30% of the energy it contains, against 5 to 10% for carbohydrate and 0 to 3% for fat. Some of a protein calorie is spent processing that protein calorie. This is one of the mechanisms behind protein’s advantage, and none of the four factors above capture it.

None of that makes the split useless. It makes it a plan with error bars, which is the correct way to hold any nutrition number. If the scale and the mirror disagree with the arithmetic after a few weeks, believe them.

Where the numbers come from

Before and after this page

This page needs a calorie target to divide. If you do not have one, the calorie target calculator works it out from your age, sex, height, weight and activity, and is honest about why the projected dates on it are optimistic.

If protein is the part you care about — and by the evidence above it should be — the protein intake calculator goes further than the floor here: it works the figure out from body weight, training and goal directly, rather than as a minimum applied to a percentage.

Assumptions

What this calculator assumes

The calorie target you enter is right. Everything here is proportional to it, so an error there is an error in all three columns.
The general Atwater factors apply to your food. High-fibre days are over-counted; very high-protein days are slightly over-counted through the thermic effect.
You are not drinking alcohol, or you have already subtracted it from the target. Nothing here has a column for 7 kcal a gram.
The protein floor is a floor, not a target. It only ever raises protein, and it never lowers it below what the percentage gives.
Meals are equal. Real days are not, and they do not need to be — the per-meal figures are for planning, not a rule.
Pounds are converted at exactly 0.45359237 kg per pound before the per-kilogram floor is applied.

Common questions

Macro FAQ

What is the best macro split?

For protein, there is a defensible answer: more than most people eat, roughly 1.6 grams per kilogram of body weight for someone training, with little further benefit past about 2.2. For the carbohydrate-to-fat split there is no best. Controlled trials that match calories and match protein find very little separating low-carb from low-fat on fat loss. What differs is adherence, and adherence is personal: pick the ratio that leaves you full, lets you train, and fits the food you actually like. That is not a cop-out — it is the finding.

How much protein should I eat a day?

For most adults doing resistance training, around 1.6 g per kilogram of body weight per day covers it; a 2018 meta-analysis put the point of diminishing returns near 1.6 with a confidence interval reaching about 2.2. Someone in a calorie deficit generally wants to sit at the higher end, because protein is what protects lean mass when energy is short. Sedentary adults need much less — the US RDA is 0.8 g/kg — though that figure is a minimum to prevent deficiency, not an optimum.

Why do the grams and the calories not multiply back exactly?

Because the percentage fixes the calorie share and the grams are that share divided by the Atwater factor, then rounded to something you can weigh. Thirty percent of 2,000 kcal of fat is exactly 600 kcal, which is 66.67 g, which prints as 67 g — and 67 × 9 is 603. The three-calorie gap is rounding, not a mistake. The alternative is gram targets with two decimal places, which nobody uses.

Does alcohol count as a macro?

It is the fourth macronutrient, at 7 kcal per gram, and no preset here accounts for it. That is a real gap, not an oversight: if you drink 300 kcal in an evening, either your day is 300 kcal over the target the split was built for, or those calories have to come out of the other three. Alcohol also blunts the muscle-protein response to training and disrupts sleep, so the honest handling is to subtract it from the calorie target before splitting, and to treat what is left as the day you are actually planning.

Is a keto split safe?

It is a long way outside the ranges the US Institute of Medicine published as acceptable — its Acceptable Macronutrient Distribution Ranges are 10 to 35% protein, 45 to 65% carbohydrate and 20 to 35% fat, and a 25/5/70 keto split sits outside two of the three. That does not make it dangerous, and ketogenic diets are used clinically for epilepsy and studied for other conditions. It does mean it is a considered departure rather than a default, and it is worth having a clinician in the loop if you have kidney, liver, pancreatic, or lipid concerns.

Do I need to hit my macros at every meal?

No. Total daily intake is what drives body composition; the per-meal figures on this page exist to make the day plannable, not because the split has to be repeated four times. Protein is the one worth spreading — distributing it reasonably evenly across three or four meals appears modestly better for muscle protein synthesis than loading it all at dinner — but carbohydrate and fat can sit wherever they suit your day and your training.

Primary sources

Sources and review notes

The arithmetic is a division and will not go stale. The guidance around it can: protein recommendations have drifted upward over two decades as better-controlled trials have accumulated, and the acceptable distribution ranges are a committee output that gets revisited. Where a clinician working with you disagrees with anything on this page, take theirs.