Macro Calculator

What Are Macronutrients?

Macronutrients are the three main types of nutrients your body needs in large quantities for energy, growth, and bodily functions. Every calorie you eat comes from one of these three sources:

• Protein (4 kcal/g) — Builds and repairs muscle, supports immune function, and keeps you feeling full. Found in meat, fish, eggs, dairy, legumes, and tofu.
• Carbohydrates (4 kcal/g) — Your body's preferred energy source, especially for the brain and high-intensity exercise. Found in grains, fruits, vegetables, and starchy foods.
• Fat (9 kcal/g) — Essential for hormone production, vitamin absorption, and cell health. Found in oils, nuts, avocados, butter, and fatty fish.

The ratio between these three macros — not just total calories — affects your body composition, energy levels, and how sustainable your diet feels long-term.

Choosing Your Diet Type

There is no universally "best" macro split. The right choice depends on your goals, preferences, and how your body responds. Here are the five approaches this calculator supports:

Start with Balanced if you're unsure — it provides adequate amounts of all macros without extreme restrictions. You can always adjust after 2–4 weeks based on how your body responds.

How Much Protein Do You Really Need?

Protein requirements vary significantly based on activity level, goals, and body composition. Here are evidence-based ranges per kilogram of bodyweight:

If you're strength training while in a calorie deficit, aim for the higher end (1.6–2.2 g/kg). Spreading protein intake evenly across 3–4 meals maximizes muscle protein synthesis throughout the day.

From a Calorie Target to Grams on a Plate

Every macro split is a division problem. You start with a calorie number and decide how much of it arrives as protein, how much as fat, and how much as carbohydrate. Percentages make that look tidy. Grams are what you buy, weigh and eat.

Set them in that order: protein first, then a floor under fat, then carbs with whatever remains. Each step earns its place. Protein defends lean mass while you are eating less than you burn. Fat below a certain intake starts costing you elsewhere, and Whittaker and Wu's 2021 meta-analysis of intervention studies found low-fat diets lowered total testosterone in men by roughly 10 to 15%. Carbohydrate is the flexible one; the Institute of Medicine's 2005 DRI report sets its RDA at 130 g a day, a figure derived from what the brain burns.

Marta is 32, stands 168 cm and weighs 72 kg. She trains four days a week and wants to lose fat. Here is her target built from the bottom up, every term substituted.

That 26/44/30 lands close to the balanced preset in the table above, which is the useful part. Work upward from grams and a sensible ratio falls out on its own. Pick the ratio off a chart first and you can end up with a protein figure that has nothing to do with the body eating it.

Her 58 g of fat sits well above the floor. The Institute of Medicine's acceptable range for adults starts at 20% of calories, which on 1,746 kcal is 39 g. Dropping to that line buys back 171 kcal of carbohydrate, which is a defensible trade for a short block before a race. Living there for months while dieting is where the hormone and fat-soluble-vitamin arguments start to bite.

Scaling protein to scale weight breaks down at the top of the BMI range. Piotr is 45, 178 cm and 118 kg, a BMI of 37. At 1.6 g/kg he would be chasing 189 g of protein a day, and the mass driving that figure is mostly fat, which needs no protein to maintain. Scale to a reference weight instead: a BMI of 25 at 178 cm works out to 79 kg, and 1.6 g/kg of that is 126 g. Sixty-three grams a day less, with every kilogram of muscle he actually carries still covered. The protein calculator runs both versions side by side.

A Day That Hits 115 g / 191 g / 58 g

Targets in grams are only worth setting if food maps onto them. Here is one ordinary day built on Marta's numbers, with quantities as eaten.

Seven grams of protein over, five grams of carbs under, three grams of fat under. No scale would register the difference. Landing within about 10 g of each target is the working standard, and chasing the last gram spends attention you will want for the next three weeks.

Notice where the protein comes from. Four items carry almost all of it: the yogurt, the chicken, the skyr and the salmon. Remove the chicken alone and the day falls 40 g short, with nothing in the rest of the menu big enough to cover it. Building each meal around a protein source and filling in afterwards is how the target gets hit without arithmetic at 9pm, and a list of high-protein foods worth keeping in the fridge does most of the work in advance.

Common Splits, and Who Each One Suits

Once protein is adequate, the rest of the split is largely a preference question. These three all run on Marta's 1,746 kcal, so the only thing changing between rows is where the calories sit.

Here is the part most macro calculators leave out. Sacks and colleagues (NEJM, 2009) randomised 811 overweight adults to four diets with different fat, protein and carbohydrate targets. At two years, every group had lost about 4 kg, and the variable that predicted loss was how many group sessions people attended. Which ratio you pick mostly decides how the diet feels day to day. Whether you keep eating it decides the result.

Adjusting After Three to Four Weeks

Every number this calculator produced is an estimate stacked on another estimate. Mifflin-St Jeor predicts your resting burn. The activity factor is a guess you made about your own week. The deficit assumes your logging is honest. Three or four weeks of real weight data outranks all of it.

• Weigh daily, read weekly. Day-to-day weight moves with water, sodium and last night's dinner. Compare the average of week four against the average of week one and ignore everything in between.
• Change calories before you change the ratio. If the weekly average is flat and the logging holds up, cut about 10% — 175 kcal on Marta's 1,746 — and hold the new number for another three weeks.
• Take the change out of carbs and fat. Protein stays fixed in grams. Those 175 kcal are about 44 g of carbohydrate, or 19 g of fat, or a split of the two.
• Recalculate every 5 kg. Marta at 67 kg has a BMR 50 kcal lower and a maintenance 78 kcal lower, which is a sixth of her original deficit gone without her deciding anything.
• Suspect the logging first. Dietary intake research documents under-reporting of 20% and more, which makes a working deficit look broken. The logging errors that hide a real deficit is the cheaper thing to fix.

Appetite suppression flips this whole problem around. On GLP-1 medication, total intake often lands well under target, and protein is usually the first thing to slide, because protein-dense foods are the ones that feel heaviest. The gram targets above do not change; hitting them takes more planning and more liquid protein. Our guides on protein intake on GLP-1 medication and protecting muscle during GLP-1 treatment cover the nutrition side. Anything to do with the medication itself belongs with your prescriber.

Tips for Hitting Your Macros

• Prioritize protein first. Plan each meal around a protein source (chicken, fish, eggs, legumes), then fill in carbs and fats around it.
• Prep in bulk. Cook protein and carb sources in batches so you always have macro-friendly options ready.
• Don't fear imperfection. Being within ±10% of your targets daily is more than enough — consistency matters more than precision.
• Track for 2–4 weeks, then calibrate. Use a tracking app to build awareness of portion sizes, then transition to intuitive eating once you know your go-to meals.
• Adjust fat around carbs. On high-carb days (training), lower fat slightly. On rest days, you can eat more fat and fewer carbs.
• Eat whole foods mostly. 80% of your intake from minimally processed foods makes hitting micros and fiber targets almost automatic.

Macro Questions People Actually Ask

• How do I turn a calorie target into grams of protein, carbs and fat?
  Set protein first, put a floor under fat, and give carbs the remainder. On a 1,746 kcal target for a 72 kg woman that is 115 g of protein at 1.6 g/kg, 58 g of fat at 0.8 g/kg, and the leftover 764 kcal as 191 g of carbohydrate. Protein and carbs are 4 kcal per gram, fat is 9.
• What is the best macro split for fat loss?
  Once protein is adequate, the ratio barely matters. Sacks and colleagues (NEJM, 2009) put 811 overweight adults on four diets with different fat, protein and carbohydrate targets, and at two years every group had lost about 4 kg. Attendance at the group sessions predicted the result; the assigned split did not.
• Should I use my current weight or my goal weight for protein?
  Current weight works up to roughly a BMI of 30. Above that, scale to a reference weight instead. A 178 cm man at 118 kg would be chasing 189 g of protein a day at 1.6 g/kg, against 126 g if you scale to the 79 kg that a BMI of 25 represents at his height. Fat mass needs no protein to maintain.
• How low can I take fat before it becomes a problem?
  The Institute of Medicine's acceptable range for adults starts at 20% of calories, which is 39 g on a 1,746 kcal target. Below that you are squeezing essential fatty acids and the carriers for vitamins A, D, E and K. Whittaker and Wu's 2021 meta-analysis of intervention studies also found low-fat diets lowered total testosterone in men by roughly 10 to 15%.
• Do I have to hit my macros exactly every day?
  Within about 10 g of each target is fine, and the weekly average matters more than any single day. A day landing 7 g of protein over and 5 g of carbs under is a hit.
• Why do two macro calculators give me different numbers?
  They use different BMR equations, different activity factors, or different default ratios, and the activity factor does the most damage. Moving from 1.375 to 1.55 on a 1,449 kcal BMR shifts maintenance by 253 kcal before anything is split into grams.
• When should I change my macros?
  After three to four weeks of consistent logging, if the weekly average weight has not moved the way you wanted. Cut or add about 10% of calories, keep protein fixed in grams, and take the change out of carbs and fat. Recalculate the whole thing every 5 kg of weight change.
• Do macros matter more than total calories?
  Calories decide the direction of weight change; macros decide what that weight consists of. Two 1,746 kcal days at 60 g and at 115 g of protein move the scale the same way and leave different amounts of muscle behind, which is why protein comes first.