Macro calculator

How your macro split is calculated

The calculator turns one calorie target into three numbers: grams of protein, fat and carbohydrate to eat each day. It works in a fixed order, protein first, then fat, then carbohydrate, because protein and fat are set from your bodyweight and a percentage, and carbohydrate simply fills whatever is left.

Step 1: your calorie target

You can type a daily calorie target directly, or let the calculator build one from your stats. When it builds one, it estimates resting energy with the Mifflin St Jeor equation, the same formula used in the calorie deficit calculator, multiplies it by an activity factor for your training volume, then adjusts for your goal: about 20 percent below maintenance to lose weight, unchanged to maintain, or roughly 15 percent above to gain.

Step 2: protein from bodyweight

Protein is set as grams per kilogram of bodyweight, not a percentage of calories, because the amount your muscle needs does not change just because your calorie target did. This calculator uses 2.2 g/kg on a lose goal to protect muscle in a deficit, 1.8 g/kg to maintain, and 1.6 g/kg to gain. That 1.6 g/kg is the point a 2018 meta-analysis found gains in healthy adults doing resistance training plateau, with the upper bound of its confidence interval at 2.2 g/kg, which is why 2.2 is the ceiling this calculator reaches for rather than a target on its own.

Step 3: fat from a percentage, carbs from what is left

Fat is set as a percentage of total calories, adjustable in steps of 20, 25, 30 or 35 percent, the range recommended for general health and athletic performance. Multiply calories by the percentage and divide by 9 kcal per gram of fat. Whatever calories remain after protein and fat go to carbohydrate, divided by 4 kcal per gram.

As a worked example, at 2,200 kcal, 70 kg, on a lose goal with 25 percent fat: protein is 2.2 times 70, which is 154 g, or 616 kcal. Fat is 2,200 times 0.25, which is 550 kcal, or 61 g. Carbohydrate takes the remaining 1,034 kcal, which is 259 g.

Why grams per kilogram, and not a fixed percentage

Some macro calculators set protein as a flat percentage of calories, for example 30 percent protein, 40 percent carbs, 30 percent fat. That is simple to remember but it breaks at the extremes: because calories scale sub-linearly with bodyweight, a 50 kg person on 30 percent protein ends up with more than the research supports, often above 2.4 g/kg, while a 100 kg person on that same 30 percent sits nearer the middle of the range at maintenance, around 2.0 g/kg, and only drops toward the bottom of it, near 1.6 g/kg, in a deficit, where they can end up short.

Grams per kilogram of bodyweight

Protein needs scale with lean mass, not with calorie intake, so grams per kilogram tracks the research directly. It also stays stable if you change your calorie target: dropping calories to lose faster does not lower how much protein you need to preserve muscle, it raises it, which is why the lose preset here uses the top of the range instead of the bottom.

Grams per pound, the US shorthand

Many US coaches use 1 g per lb of bodyweight, which works out to about 2.2 g/kg, coincidentally the top of the researched range. It is an easy number to remember, but it is really just one point on the same 1.6 to 2.2 g/kg scale this calculator uses.

Percent of calories

A flat percentage is easier to build meal templates around but has no direct link to bodyweight, so it needs constant rechecking whenever the calorie target changes. It shows up more often in bodybuilding meal plans than in the sports nutrition literature.

Why a 20 to 35 percent fat range

Dietary fat carries essential fatty acids and supports hormone production, so it has a floor as well as a ceiling. The joint position statement from the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine puts the useful range for active adults at 20 to 35 percent of calories, and this calculator defaults inside that range at 25 percent.

Below 20 percent, fat intake is hard to sustain over the long run and can affect hormone levels and the absorption of the fat soluble vitamins A, D, E and K. Above 35 percent, there is usually not enough room left for the carbohydrate that fuels training, especially once calories are already reduced for weight loss.

There is no single best number inside the range, and the calculator lets you move it. Someone training twice a day usually leans toward the lower end to leave more room for carbohydrate; someone doing mostly strength work two or three times a week can comfortably sit at 30 to 35 percent without it costing them anything in the gym.

Essential fatty acids you cannot make yourself

Two fats are essential, meaning the body cannot build them from carbohydrate or protein and has to get them from food: linoleic acid, an omega-6, and alpha-linolenic acid, an omega-3. Both sit in cell membranes throughout the body and feed into the hormones that regulate inflammation, blood clotting and immune response. Cholesterol synthesis and several sex hormones also depend on having enough dietary fat available, which is why the range has a floor and not just a ceiling. None of this shows up overnight; a diet that runs fat very low for weeks or months, well under the 20 percent floor this calculator sets, is the scenario where a shortfall in either fat starts to matter.

Fat for strength work versus endurance work

The right number inside 20 to 35 percent depends partly on what kind of training the calories are fuelling. Someone training mostly for strength or power, two or three heavy sessions a week with plenty of rest between them, does not burn through much glycogen, so sitting at the top of the range, 30 to 35 percent, rarely costs them anything in the gym and can make a high calorie bulk noticeably easier to eat, since fat packs more calories per gram than carbohydrate or protein. Someone training for endurance, or doing two sessions a day, is depleting glycogen fast enough that the same 35 percent fat leaves too little room for the carbohydrate those sessions actually run on, so the lower end of the range, 20 to 25 percent, tends to hold up better across a training week.

Protein timing, and how the split changes for body recomposition

Total daily protein matters far more than exactly when you eat it, but timing and a body recomposition goal both change how you would put these numbers into practice day to day.

How often you need to eat it

The ISSN position stand recommends spreading protein across the day in 20 to 40 g doses every three to four hours rather than prescribing a fixed number of meals. Each dose of protein only stimulates muscle protein synthesis for a few hours before another one is needed to restart it, which is why spacing matters more than hitting an exact meal count. Three to five servings of 30 to 40 g each comfortably satisfies that spacing without needing to plan meals around a clock, roughly the range the how to use section below recommends.

Protein before sleep

A serving of 30 to 40 g of a slow digesting protein, such as a dairy based shake, cottage cheese or a mixed meal eaten close to bedtime, modestly raises muscle protein synthesis overnight compared with going to bed without it. It is not required to hit your goals, but if you already have a serving of your daily total left over in the evening, moving it close to bedtime rather than skipping it is close to free.

Body recomposition: losing fat and gaining muscle at the same time

Recomposition, changing body composition without much net change on the scale, does not fit neatly into the lose, maintain or gain presets this calculator uses, because it usually means eating at or only slightly below maintenance rather than a clear deficit or surplus. Protein should sit at the top of the range this calculator reaches for, 2.0 to 2.2 g/kg, since it is doing double duty: preserving muscle without the help of a calorie surplus, and supporting the repair a resistance training programme demands on top of that. Fat and carbohydrate then split whatever calories remain, with carbohydrate weighted toward training days so the hardest sessions are not run on close to empty. Recomposition tends to work best for people newer to structured training, or returning after time off, since their body has the most room to add muscle without a surplus; someone already lean and experienced usually makes faster progress by picking a clear lose or gain phase instead and alternating between them.

Macro splits by goal, at a glance

The table shows the default split this calculator produces for each goal, worked out for a 75 kg person on a 2,400 kcal maintenance and 25 percent fat. Your own numbers will differ with your calorie target and bodyweight, but the pattern, protein and fat holding roughly steady while carbohydrate moves with the calorie target, holds for everyone.

How to use your macro numbers

Hit protein first, every day, before worrying about the other two. It is the macro most linked to body composition outcomes and the easiest one to fall short on when a day gets busy.

Spread protein across the day

Three to five servings of 30 to 40 g each is easier to hit and use than trying to eat it all in one sitting. The protein calculator can help you check individual meals against the daily total.

Treat fat and carbs as flexible day to day

Once protein is fixed and fat sits inside 20 to 35 percent, the exact carbohydrate number matters less on any single day than hitting it most days across a week. Swapping 20 g of carbs for a similar amount of fat on one day will not change your results; swapping most of your carbohydrate for fat every day for a month will.

Recalculate when your weight or goal changes

Protein and fat both move with bodyweight and calorie target, so a split set at 80 kg is out of date at 72 kg. Rerun the numbers whenever you update your calorie deficit or bulking calories, not just once at the start.

Common mistakes with macros

Setting protein too low. Below about 1.4 g/kg, most people struggle to preserve muscle in a deficit. If tracking feels tight, trim carbs or fat before trimming protein.

Chasing a round percentage. 40/30/30 is easy to say but was not derived from your bodyweight. Two people the same height can need very different protein grams at the same percentage.

Cutting fat to almost zero. Dropping fat below 20 percent to make room for more carbohydrate usually shows up as low energy and poor hormone markers within a few weeks, not immediately, which is why it often goes unnoticed until it is a pattern.

Never adjusting for weight change. A macro split does not update itself. Ten kilograms of change without a recalculation leaves the protein target 16 to 22 g off from what it should be.

Hitting calories but missing macros. The calorie total is necessary but not sufficient. Two days at the same calories with very different protein intakes can produce different results over months of training.

Tracking and adjusting your split

Most food tracking apps let you set custom macro targets instead of the app default. Enter the grams from this calculator directly rather than percentages, since grams are what you actually weigh out.

Give it two weeks before judging it

Macros interact with training and recovery over time, not meal to meal. Judge the split on how training performance, hunger and the weekly weight trend look after two consistent weeks, not after one heavy or one hungry day.

Training days versus rest days

Some people shift 20 to 30 percent of daily carbohydrate toward training days and away from rest days, keeping protein and fat flat across the week. It is optional. It changes when carbohydrate is eaten, not how much of it there is overall, and suits people who feel flat training on a low carb day.

Reading the trend against what you logged

The weekly weight trend and your logged macro adherence only mean something read together, not apart. Weight trending down with protein and calories consistently hit is the split working as intended, no changes needed. Weight flat with the same numbers consistently hit for two or three full weeks means the calorie target itself is too high for the current goal, so lower calories and let fat and carbohydrate absorb the change, protein stays where it is. Weight trending down but logged macros missing most days tells you nothing useful about the split, because you do not actually know what was eaten, so the fix is tightening logging before touching any number. The case worth watching is weight flat while logged macros are also inconsistent: it looks like a plateau but is often just noisy data, and a week of genuinely complete logging before any change usually clears it up faster than adjusting a split you cannot yet trust the input to.

How coaches use a macro calculator

For a coach, the macro split is the daily instruction a calorie target turns into. A client can act on "eat 150 g protein, 60 g fat, 200 g carbs" in a way they cannot act on "eat 1,900 kcal".

A workable routine: set the calorie target and goal at onboarding, hand over the three macro numbers, then review adherence and the weekly weight trend every check-in rather than the day-to-day grams.

Where the error actually comes from

Coaches who compare a calculator number against a client's real-world results sometimes conclude the formula is wrong. Most of the time the bigger error is upstream of the formula: a food scale that is never used, portions estimated by eye, sauces and cooking oil left off the log, or a bathroom scale weighed at a different time of day each morning. A g/kg protein target and a Mifflin St Jeor calorie estimate are both accurate to within a modest margin under good measurement. Under loose logging, that margin gets swamped by measurement error long before the formula itself is the limiting factor, so the first fix for a client who is not responding is almost always tighter logging for one to two weeks, not a different equation.

Templating across a caseload

For a coach running the same split logic across many clients, the part worth standardising is the method, not the numbers: same g/kg protein table by goal, same 20 to 35 percent fat range, same rule for when to recalculate. The individual grams will differ by bodyweight and calorie target, but a consistent method means a client moving between programmes, or a new client filling out an intake form, gets a split built the same way every time rather than one that depends on which day it was calculated by hand.

Scraler builds a macro target into every client's nutrition plan, tracks what they log against it automatically, and surfaces adherence in your check-ins instead of you recalculating splits by hand for each client. If you coach both training and nutrition, hybrid personal training covers how the two combine.