Macro calculator for bodybuilding
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.
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.
Track your progress, not just your calculations
Log your workouts, loads and weight, and watch your curve climb — for free.