The math, made boring
How to Calculate Macros (Plain English)
Last updated: 2 May 2026
Macros, short for macronutrients, are the three categories of food that supply calories: protein, carbohydrates, and fat. Calculating macros is just splitting your daily calorie target into grams of each. The math is fifth-grade arithmetic. We will walk through it step by step, then run a full worked example.
- Protein: 4 calories per gram
- Carbohydrates: 4 calories per gram
- Fat: 9 calories per gram
Alcohol, for the curious, is 7 calories per gram, but it does not get its own macro target.
The five-step method
Every credible macro calculator does these five things in order. You can do them yourself in five minutes.
- Find your TDEE. Use our TDEE calculator or the Mifflin-St Jeor equation.
- Adjust for your goal. Subtract 15 to 25% for cutting, leave it at TDEE for maintenance, add 5 to 15% for lean bulk.
- Set protein in grams. Use a g/kg bodyweight number based on your goal and training.
- Set fat in grams. Minimum 0.4 to 0.6 g/kg for hormones, then flex up if you prefer fat over carbs.
- Carbs fill the remainder. Whatever calories are left after protein and fat go to carbs.
That is the whole thing. The reason it is structured this way is biological priority: protein has hard requirements for muscle and recovery, fat has hard requirements for hormone production, and carbs are flexible fuel that scales with how hard you train.
Step 1 and 2: Calorie target
Run your TDEE first. For most people in our calculators that lands somewhere between 1,800 and 3,000. Then apply your goal:
- Cutting: TDEE × 0.80 (a 20% deficit) is a strong default. More aggressive than 25% is rarely worth it. See our TDEE for weight loss guide for why.
- Maintenance: Eat at TDEE.
- Lean bulk: TDEE × 1.10 is a sensible default. More than +15% adds fat without adding more muscle.
Step 3: Set protein
Protein is the macro everyone underestimates. Decades of research (summarized in Phillips et al., 2016 and Helms et al., 2014 for natural lifters) converge on the following ranges. Pick the row that matches you:
| Profile | Protein (g/kg bodyweight) | Example: 75 kg adult |
|---|---|---|
| Sedentary, no training | 0.8 g/kg | ~60 g |
| Recreational lifter or athlete (maintenance) | 1.4 to 1.8 g/kg | 105 to 135 g |
| Cutting, training hard | 1.6 to 2.2 g/kg | 120 to 165 g |
| Lean cutter (already <15% body fat) | 2.0 to 2.4 g/kg | 150 to 180 g |
| Lean bulk | 1.6 to 2.0 g/kg | 120 to 150 g |
If you are very overweight, use g/kg of target bodyweight or g/kg of lean mass instead. Otherwise the protein number gets unreasonably large. For example, a person at 130 kg targeting 90 kg should use ~90 kg in the formula, giving a protein target around 145 to 200 g rather than 200 to 290 g.
Once you pick a g/kg, multiply by your bodyweight in kg to get total grams. Multiply grams by 4 to get protein calories.
Step 4: Set fat
Fat is the macro people fear unnecessarily and sometimes underconsume. The minimum for healthy hormone function (testosterone, estrogen, cortisol balance) sits around 0.4 to 0.6 g/kg of bodyweight, per ISSN position stands and multiple intervention trials. Below that, lipid panels and hormone markers can shift in unfavorable directions over months.
For most people, a sensible fat target is:
- Floor: 0.6 g/kg bodyweight (75 kg adult: 45 g fat = 405 kcal)
- Default: 0.8 to 1.0 g/kg (75 kg adult: 60 to 75 g fat = 540 to 675 kcal)
- Higher-fat preference: up to 1.2 g/kg if you prefer fat over carbs
Multiply grams by 9 to get fat calories.
Step 5: Carbs fill the rest
Subtract protein calories and fat calories from your total. Whatever is left goes to carbs. Divide by 4 to get carb grams.
If you train hard (4+ intense sessions per week, especially endurance or high-volume lifting), you generally want carbs in the 3 to 5 g/kg range or higher. If your "carbs leftover" math gives you less than that, consider lowering fat slightly to free up calories for carbs. If you train very little, anything 1 to 2 g/kg works fine and the rest can stay as fat.
Standard splits as a sanity check
If you want a faster shortcut, here are the percentage splits we use as defaults in our macros calculator. Use them to check that your custom split is roughly in the same neighborhood.
| Goal | Protein | Carbs | Fat |
|---|---|---|---|
| Cutting | 40% | 35% | 25% |
| Maintenance | 30% | 45% | 25% |
| Lean bulk | 30% | 50% | 20% |
| Endurance training | 25% | 55% | 20% |
| Higher-fat preference | 30% | 30% | 40% |
These are starting points, not laws. Your real numbers come from the step-by-step method above. Think of percentages as a check: if your custom plan lands at 50% protein for a maintenance lifter, something is off.
Worked example: 75 kg male, moderate activity, cutting
Let's run the full math for one person. He is 30 years old, 175 cm tall, 75 kg, trains 4 times per week with weights, has a desk job. Goal: lose ~6 kg over 16 weeks.
1. TDEE
Mifflin-St Jeor BMR for men: 10(75) + 6.25(175) − 5(30) + 5 = 750 + 1,094 − 150 + 5 = 1,699 kcal.
Activity multiplier: 1.55 (moderate, 4 hard sessions on a desk-job lifestyle).
TDEE = 1,699 × 1.55 = 2,633 kcal.
2. Goal target
Cutting at 20% deficit: 2,633 × 0.80 = 2,106 kcal/day. Round to 2,100.
3. Protein
Cutting + training hard: 2.0 g/kg. Total = 75 × 2.0 = 150 g protein. Calories: 150 × 4 = 600 kcal.
4. Fat
Default for cutting: 0.8 g/kg. Total = 75 × 0.8 = 60 g fat. Calories: 60 × 9 = 540 kcal.
5. Carbs
Remaining calories: 2,100 − 600 − 540 = 960 kcal. Carbs = 960 / 4 = 240 g.
Final macros
- Calories: 2,100
- Protein: 150 g (29% of calories)
- Carbs: 240 g (46% of calories)
- Fat: 60 g (26% of calories)
This is a workable, sustainable cutting plan. Carbs at 3.2 g/kg support training. Protein at 2 g/kg protects lean mass. Fat is well above the floor. Total deficit is moderate, which means he should lose ~0.5 kg per week and still feel human in week 12.
IIFYM: a quick note
IIFYM stands for "If It Fits Your Macros". The idea is simple: as long as you hit your calorie and macro targets, the specific foods do not matter much. A donut and a banana that contribute the same macros affect your body composition the same.
This is technically correct. It is also incomplete.
- What IIFYM gets right: body composition is overwhelmingly determined by total calories and total macros. Forbidding entire food categories is unnecessary for most people.
- What it underplays: food quality affects satiety, micronutrients, fiber, and how easy your plan is to follow. A 2,100-calorie day of mostly whole foods has different consequences (less hunger, better sleep, more micronutrients) than a 2,100-calorie day of mostly processed snacks, even at identical macros.
Reasonable rule of thumb: 80 to 90% of your food from minimally processed sources, 10 to 20% flexibility. You hit your macros, you keep your sanity, and your micronutrients take care of themselves.
Vegan and vegetarian considerations
Plant-based eaters can hit any macro split, but two things deserve real planning:
- Protein: per-gram, plant proteins (lentils, beans, tofu, tempeh, seitan, peas, soy products) are lower-density than animal proteins. Hitting 1.8 to 2.2 g/kg requires deliberate inclusion of high-protein plant foods at every meal, often supplemented by a protein powder (pea, soy, or rice). It is doable, just not automatic.
- Leucine: plant proteins are slightly lower in leucine, the amino acid that triggers muscle protein synthesis. Practical fix: aim for the higher end of the protein range (2.0 to 2.2 g/kg) rather than the lower end, and spread protein across 4 to 5 meals.
Other plant-eater specifics (B12, omega-3, iron, zinc) are real but micronutrient questions, not macro questions. They do not change how you split your calories.
Skip the math.
Our free macros calculator runs the full sequence above in one click and returns your daily targets in grams. Pair it with the TDEE calculator for the full setup.
FAQ
Do macros matter more than calories?
Calories are the bigger lever for weight change. Macros (especially protein) are the bigger lever for body composition. For weight loss alone, hitting a calorie deficit with any reasonable macro split works. For losing fat while keeping muscle, hitting a protein target inside that deficit matters significantly. Both, not either.
Are macros different for women?
The g/kg targets above apply to women too. The relative split is similar. The total calorie target is usually lower because TDEE is lower on average. There is no need for a separate "women's" macro framework. For more on female-specific factors, see our TDEE for women guide.
Should I count fiber as carbs?
In the US, food labels include fiber in total carbohydrates. In the UK, EU, and India, labels typically list net carbs (excluding fiber). Either approach works for tracking. Fiber has minimal calorie contribution and beneficial effects on satiety and digestion. We recommend tracking total carbs and aiming for 25 to 35 g of fiber per day separately, rather than subtracting fiber from your carb target.
What about carb cycling?
Carb cycling means high-carb days on hard training days, lower-carb days on rest days, with protein and total weekly calories held constant. Direct studies (Davoodi et al., 2014 and others) show modest or no advantage over flat daily intake at the same weekly calories. It is a tool, not magic. Use it if it fits your appetite and training schedule. Skip it if it adds friction.
Do I need to hit macros exactly?
Within ±5 g protein, ±5 g fat, and ±10 to 15 g carbs is plenty close. Hitting exact whole numbers daily is precision theater. Trends across a week beat single-day perfection.
How long until I see results?
Visible body composition change typically takes 4 to 8 weeks of consistent macro hitting. The scale moves earlier (some of that is water and gut content). Photos and tape measurements are better progress signals than scale weight alone, especially for beginners adding muscle while losing fat.