Macro Calculator
Calculate daily protein, carb, and fat targets.
đ Runs entirely in your browser â nothing is uploaded.
âšī¸ Estimates based on the Mifflin-St Jeor formula - not medical advice. Consult a professional for personalized nutrition guidance.
Percentages should add up to 100 (currently ).
How Macro Calculator works
How are the protein, carb, and fat targets worked out?
It first calculates daily calories the same way the calorie calculator does - a Mifflin-St Jeor BMR times an activity multiplier, then adjusted by your goal (0.8Ã for weight loss, 1Ã for maintenance, 1.15Ã for weight gain). That calorie total is then split across the protein, carb, and fat percentages you set, converting each using 4 calories per gram for protein and carbs and 9 calories per gram for fat.
When would I use this instead of a plain calorie calculator?
It's built for anyone tracking macros deliberately - for example lifters following an if-it-fits-your-macros style plan who want gram targets, not just a calorie ceiling. Because the percentage split is adjustable, you can also model different macro strategies, like higher protein or lower carb, against the same calorie budget.
Are the default percentages the "right" split?
The default 30% protein / 40% carbs / 30% fat is just a starting point, not a scientifically prescribed ratio, and the fields are fully editable - the tool will flag it if your percentages don't add up to 100. These are general estimates and not medical or dietary advice; specific conditions like diabetes or kidney disease call for guidance from a doctor or registered dietitian.