Macro calculator for bodybuilding
Updated on 18 September 2026
Your daily macros start from your target calories (basal rate via Mifflin-St Jeor × activity, adjusted to your goal): protein is set from body weight, fat at 25-28% of calories, and carbs take the remainder.
This complete calculator starts from your body stats to estimate your target calories (Mifflin-St Jeor formula), then splits them into protein, fat and carbs based on your goal. No need to know your calories in advance — it is all worked out in one go.
Fill in your age, height and weight: the tool computes your target calories, then your macros.
How the calculator works
The tool first computes your basal metabolic rate with the Mifflin-St Jeor formula (sex, age, height, weight), then multiplies it by your activity level to get your daily energy expenditure — your maintenance calories.
It then applies your goal: -15% for cutting, maintenance, or +10% for bulking. Those target calories are what get split into macros — the same basis as our calorie calculator, so the numbers stay consistent between the two tools.
The split logic
The tool first sets protein based on your weight (the priority macro), then fat at a level sufficient for hormonal health (about 25-28% of calories). Carbs take the rest: they are what fuel your sessions.
This hierarchy is no accident: protein and fat have floor requirements to respect, while carbs adjust to the energy you need. On a bulk they rise; on a cut they fall.
Bulking vs cutting: what changes
Bulking aims for a small calorie surplus with enough carbs to fuel heavy sessions: protein stays high (2 g/kg), carbs rise. Cutting runs a deficit while pushing protein up (2.2 g/kg) to preserve muscle, so carbs fall accordingly.
That is why macros "for bodybuilding" only make sense tied to a goal: the same calories are not split the same way whether you want to gain muscle or lean out. Total calories decide your weight; the split optimises body composition.
Must you weigh everything to the gram?
No. These figures are targets, not obsessive constraints. Hitting protein closely and staying roughly on track for the rest is enough for most people to progress.
The value of the calculation is mainly educational: it teaches you what a balanced day looks like, and spares you the two classic mistakes — too little protein, or fat crushed so low it hurts recovery.
Adjusting macros in practice
If your carbs feel too high or too low for your digestive tolerance or preferences, you can swap them for fat at equal calories (1 g of fat = 9 kcal, 1 g of carbs = 4 kcal), as long as you keep protein fixed and a minimum of fat for hormonal health.
Many trainees also adjust macros by training day: more carbs on heavy session days, a bit less on rest days, at equal total weekly calories. This is an option, not a requirement.
Macros and vegetarian diets
A vegetarian or vegan diet can hit the same macro targets, but needs more attention to food volume: plant protein sources are often less dense, so you need larger portions for the same grams.
Fat rarely causes issues (oils, nuts, avocado), but watch complex carbs so you do not exceed your total calories while trying to hit protein solely through bulky legumes.
Frequently asked questions
How much protein per day to build muscle?expand_more
Aim for 1.8 to 2.2 g of protein per kilo of body weight depending on your goal — more on a cut to preserve muscle. For 75 kg that is about 135 to 165 g per day. It is the one macro not to skimp on.
What macros for bulking or cutting?expand_more
Bulking: a small surplus, protein at 2 g/kg, higher carbs for energy. Cutting: about a 15% deficit, protein at 2.2 g/kg to protect muscle, lower carbs. The tool applies these settings automatically based on the goal you pick.
Which formula does this calculator use?expand_more
It estimates your calories with the Mifflin-St Jeor equation, today's reference for basal metabolic rate, then applies an activity factor and your goal adjustment. Protein is set from body weight, fat at 25-28% of calories, carbs from the remainder.
Do carbs make you fat?expand_more
No, it is excess calories that cause fat gain, not any single macronutrient. Carbs are even the preferred fuel for strength training: cutting them to the extreme often hurts performance.
Can I adjust the split?expand_more
Yes, as long as you keep enough protein and a minimum of fat. Some prefer more carbs (useful if you train hard), others more fat. Total calories remain the decisive factor for weight.
Do these macros suit bodybuilding and strength training?expand_more
Yes. The priority given to protein and keeping carbs high enough match the needs of bodybuilding, powerlifting and most strength sports. Push carbs higher if you train very intensely or several times a day.
Do I need to hit my macros to the exact gram?expand_more
No, a margin of 5 to 10 g per macro changes nothing measurable. What matters is the weekly trend: aiming close every day beats being perfect one day and far off the next.
Do macros change with age?expand_more
Protein needs increase slightly after 50-60 to offset less efficient muscle synthesis. Fat and carb needs stay broadly stable, adjusted mainly by activity level, not age alone.
What if I cannot finish my carbs?expand_more
Favor dense, easy-to-eat sources (white rice, bread, dried fruit, juice) rather than very fiber-rich carbs that fill you up fast. This is common during a bulk, when total food volume is high.
Should macros be the same on rest days?expand_more
Not necessarily: many trainees slightly reduce carbs on days without training, since the energy demand from exercise is absent. Keep protein and fat stable, and vary mainly the carbs.
Does this calculator suit a lean bulk?expand_more
Yes: the +10% surplus applied here matches a lean bulk, which limits fat gain compared to an aggressive surplus. It is the recommended setting for most natural trainees.
What if my calories and macros do not add up exactly?expand_more
A small calculation gap (protein and carbs at 4 kcal/g, fat at 9 kcal/g) is normal after rounding the grams. A difference of a few dozen kcal has no practical impact on your results.
Are macros different for endurance sports?expand_more
Yes: endurance sports generally need more carbs (up to 55-65% of calories) to replenish glycogen stores, with a slightly lower protein need than pure strength training, around 1.2 to 1.6 g/kg.
Should you change your macros every week?expand_more
No, as long as your weight is moving as expected. Only adjust them if the trend over 2 to 3 weeks drifts from your goal, or if your body weight changes enough to recompute protein.
Are macros useful without a precise weight goal?expand_more
Yes, they also help structure a balanced daily diet, even at simple maintenance without a transformation goal. They then mainly serve as a nutritional quality marker rather than a body composition lever.
Should macros be adjusted for the type of training (strength vs cardio)?expand_more
Yes to some extent: a high volume of cardio slightly increases calorie needs and can justify more carbs, while pure strength work is well covered by the standard split offered here.
Sources
- menu_bookMifflin-St Jeor equation
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