Health · Nutrition
Macro Calculator
Turn your daily calorie target into protein, carbs and fat in grams. Pick your goal — cut, maintain or bulk — and get an IIFYM-ready split in seconds. Free, no sign-up.
How the macro calculator works
Your three macronutrients — protein, carbohydrate and fat — are what make up your calorie target. This tool fills them in a simple, evidence-aligned order:
- Protein first — set from your body weight. We use about 2.0 g/kg on a cut (to protect muscle), 1.8 g/kg at maintenance, and 1.6 g/kg on a bulk. Protein is 4 calories per gram.
- Fat next — set at 25% of your calorie target, then divided by 9 (fat is 9 calories per gram) to get grams.
- Carbs last — whatever calories remain after protein and fat go to carbohydrates, divided by 4 (carbs are 4 calories per gram). Carbs never go below zero.
Example: a 2,500 kcal target at 80 kg body weight gives about 160 g protein (640 kcal), 69 g fat (625 kcal) and 309 g carbs (1,235 kcal). Add those calories back up and you land on your target.
Calories per gram
| Macronutrient | Calories per gram |
|---|---|
| Protein | 4 kcal |
| Carbohydrate | 4 kcal |
| Fat | 9 kcal |
Things to keep in mind
These are starting points, not strict rules
The 2.0 / 1.8 / 1.6 g/kg protein levels and 25% fat are sensible defaults that work for most people. If you prefer a higher-fat, lower-carb style — or the opposite — you can shift those numbers and still hit the same calorie target. The goal is to hit your protein and your total calories consistently.
Very low calorie targets squeeze carbs
If your calorie target is low relative to your body weight, protein plus fat can use up most of your calories and leave very little for carbs. When that happens the calculator floors carbs at zero. If you see zero or near-zero carbs, your calorie target may be too low for your weight, or your protein target too high.
Frequently asked questions
How are my macros calculated?
Protein is set from your body weight (about 2.0 g/kg cutting, 1.8 g/kg maintaining, 1.6 g/kg bulking). Fat is 25% of your calorie target. Carbs get the calories left over. Protein and carbs are 4 kcal/g, fat is 9 kcal/g.
How much protein should I eat per day?
For active people, roughly 1.6–2.2 g of protein per kg of body weight per day is a common evidence-based range. This tool defaults to 2.0 g/kg on a cut, 1.8 g/kg at maintenance and 1.6 g/kg on a bulk.
What is IIFYM?
IIFYM means "If It Fits Your Macros" — a flexible-dieting approach where you hit daily protein, carb and fat targets instead of following a rigid meal plan. This calculator gives you those three targets.
Should fat really be 25% of calories?
25% is a balanced default that keeps fat above the minimum your hormones need while leaving room for protein and carbs. Treat it as a starting point you can adjust up or down.
Where do I get my calorie target?
Start from your TDEE. To lose weight, subtract ~300–500 kcal; to gain, add a similar amount; to maintain, use TDEE as-is. Our TDEE Calculator can estimate it, then plug the number in here.
What macronutrients actually are
"Macros" is short for macronutrients — the three nutrients your body needs in large amounts and that supply all of your dietary energy. They are protein, carbohydrate and fat. Every food you eat is some combination of these three, plus water and trace micronutrients like vitamins and minerals. While a calorie target tells you how much energy to eat, your macro split tells you what that energy should be made of, and that composition has a real effect on how you feel, perform, recover and hold onto muscle.
The energy value of each macro is fixed and well established. Protein and carbohydrate each provide 4 calories per gram, while fat is more energy-dense at 9 calories per gram — more than twice as much. Alcohol, for the record, supplies 7 calories per gram, though it is not a nutrient your body needs. Knowing these conversion rates is the foundation of every macro calculation: once you decide how many grams of each macro to eat, multiplying by 4, 4 and 9 tells you exactly how those grams add back up to your calorie target.
| Macronutrient | Energy per gram | Main role |
|---|---|---|
| Protein | 4 kcal | Builds and repairs muscle and tissue |
| Carbohydrate | 4 kcal | Primary fuel for training and the brain |
| Fat | 9 kcal | Hormones, cell membranes, vitamin absorption |
Why protein gets set first
This calculator deliberately sets protein before anything else, and that order reflects how most evidence-based coaches build a plan. Protein does the jobs no other macro can: it supplies the amino acids your body uses to build and repair muscle, and it is the macro most strongly linked to keeping muscle while you lose fat. It is also the most filling of the three per calorie, which makes a higher-protein plan easier to stick to when you are eating in a deficit.
A common, well-supported range for active people and anyone trying to preserve muscle is roughly 1.6 to 2.2 grams of protein per kilogram of body weight per day. This tool uses sensible defaults within that range that shift with your goal. On a cut it defaults to the higher end at 2.0 g/kg, because protein needs rise when calories are restricted and protecting muscle becomes the priority. At maintenance it uses 1.8 g/kg. On a bulk it eases to 1.6 g/kg, since you have plenty of calories and carbohydrates can do more of the work of fueling hard training.
How the goal-based split changes
Your goal does more than nudge your protein. It changes the entire shape of the day, because fat is anchored at about 25% of calories and carbohydrates absorb whatever is left over. The table below shows how the same person at 80 kg body weight ends up with very different gram targets depending on whether they are cutting, maintaining or bulking.
| Goal | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| Cut | 2,000 | 160 g | 215 g | 56 g |
| Maintain | 2,600 | 144 g | 383 g | 72 g |
| Bulk | 3,000 | 128 g | 510 g | 83 g |
Notice that as calories climb, protein in grams actually goes down slightly while carbohydrates climb sharply. That is intentional. On a bulk you have abundant energy, so you do not need to lean as heavily on protein, and the extra carbohydrate fuels the training that drives muscle growth. On a cut the reverse is true: protein stays high to protect muscle, and the limited calories squeeze carbohydrate down.
Why fat is anchored at 25% of calories
Dietary fat is not just a calorie source — it is essential. Your body needs a baseline amount of fat to produce hormones, build cell membranes and absorb the fat-soluble vitamins A, D, E and K. Setting fat at about 25% of total calories keeps it comfortably above the bare minimum most people need for health, while still leaving plenty of room for protein and carbohydrates. It is a balanced default rather than a hard rule. People who feel better on a higher-fat, lower-carb approach can shift the number up, and those who train hard and prefer more carbohydrate can shift it down, as long as fat does not drop so low that it compromises how they feel.
How to track your macros in practice
- Weigh foods at first. A cheap kitchen scale is far more accurate than eyeballing portions, and most people are surprised by how off their estimates are. After a few weeks you will be able to judge portions much better.
- Hit protein, then aim near the rest. Protein and total calories are the two numbers worth chasing precisely. Getting carbs and fat within roughly 10 grams of target is more than good enough for results.
- Use a logging app. A food-tracking app with a barcode scanner removes most of the math and stores the foods you eat often, which makes daily logging take just a few minutes.
- Don't sweat one off day. Macros are a weekly and monthly game. A single high day will not undo progress; consistency across many days is what moves the needle.
Common misconceptions about macros
"Carbs make you fat." No single macro makes you gain fat on its own — a calorie surplus does, regardless of where the calories come from. Carbohydrates are simply your body's preferred training fuel, and cutting them to zero is rarely necessary unless you specifically choose a low-carb style.
"More protein is always better." Beyond roughly 2.2 g/kg there is little added benefit for most people, and those extra protein calories could often be better spent on the carbohydrates that fuel your workouts. The defaults in this tool already sit in the effective range.
"I have to hit my macros perfectly every day." Flexible dieting works precisely because it does not demand perfection. Aim to be consistently close rather than occasionally perfect, and you will see steadier progress with far less stress.