MyGymCalcWhat Is a Macro Calculator?
A macro calculator works out how many grams of protein, carbs, and fat you should eat each day to reach your fitness goal. “Macros” is short for macronutrients, the three types of nutrients that make up your calorie intake. While a calorie calculator tells you how much to eat overall, this macro calculator breaks that number down into exactly what to eat it as, which matters just as much as total calories when you’re trying to build muscle, lose fat, or perform better in the gym.
This tool takes your daily calorie target and your goal (cutting, maintaining, or bulking), then splits it into a protein, carb, and fat target in grams, tailored to your body weight. If you haven’t calculated your calories yet, start with our Calorie Calculator first, then come back here to get your full macro breakdown.
Why Macros Matter More Than Just Calories
Two people can eat the exact same number of calories and get very different results depending on where those calories come from. Someone eating mostly protein and vegetables will build and preserve muscle far better than someone eating the same calories mostly from sugar and refined carbs, even at an identical calorie total. That’s because each macronutrient plays a different role in your body.
- Protein repairs and builds muscle tissue, and it’s the macro most directly tied to your results from strength training.
- Carbohydrates fuel your workouts and replenish the energy your muscles use during training.
- Fat supports hormone production, including hormones directly involved in muscle growth and recovery.
Hitting your calorie target without paying attention to macros often leads to poor progress: being technically “in a deficit” or “in a surplus” but still not building muscle or losing fat the way you expected.
How to Calculate Macros
This calculator does the math for you, but here’s what’s happening behind the scenes so you understand your results:
- Protein is set first, based on your body weight and training goal, since it’s the macro most tied to muscle. Typical targets range from about 1.6 to 2.2 grams per kilogram of body weight for people who train regularly.
- Fat is set next, usually around 20–30% of your total calories, since fat needs stay relatively stable regardless of your goal.
- Carbohydrates fill in the rest of your calorie target. Carbs are the most flexible macro and the one most often adjusted up or down depending on whether you’re cutting or bulking.
Each gram of protein and carbohydrate provides 4 calories, while each gram of fat provides 9 calories. This calculator uses those conversions to make sure your protein, carb, and fat grams add up to match your total calorie target exactly.
Macro Split for Cutting (Fat Loss)
When cutting, protein is kept high to protect muscle while you’re in a calorie deficit, since your body is more likely to break down muscle for energy when calories are low. Fat stays moderate to support hormone health, and carbs are reduced the most, since they’re the easiest macro to cut without much impact on muscle retention. This calculator automatically raises the protein target for cutting goals to help preserve the muscle you’ve already built.
Macro Split for Bulking (Muscle Gain)
When bulking, carbs increase to fuel harder training sessions and support the extra calories needed for muscle growth, while protein stays high to make the most of that surplus. Fat is kept at a healthy baseline rather than increased dramatically, since very high fat intake isn’t necessary for muscle gain and can make it harder to eat enough carbs and protein within your calorie target.
Macro Split for Maintenance
At maintenance, macros are kept balanced: protein high enough to maintain muscle, moderate fat for hormone health, and carbs filling the rest to support your energy needs and training performance without pushing you into a surplus or deficit.
How to Use Your Macro Results
- Track your food for the first week or two using any food app, matching your intake against the grams shown here, not just your calorie total.
- Prioritize protein first. If you’re short on time or consistency, hitting your protein target matters more than being exact on carbs and fat.
- Adjust based on real results. If you’re not seeing progress after 2–3 weeks, revisit your Calorie Calculator result and recalculate your macros from there.
- Pair with your protein needs. Check our Protein Calculator if you want a closer look at protein specifically.