Free macro calculator
Get your daily calories and your protein, carbs and fat in grams. No sign up, no email, nothing saved. The numbers update as you type.
Runs in your browser. Nothing sent, nothing stored.
Macro calculator
The method
How this macro calculator works
Three steps, all of them published formulas you can check yourself.
Your BMR, from Mifflin-St Jeor
Basal metabolic rate is what your body burns at complete rest. Mifflin-St Jeor is the equation most nutrition software defaults to, because it lands closest for the widest range of people.
Men BMR = 10 × kg + 6.25 × cm − 5 × age + 5 Women BMR = 10 × kg + 6.25 × cm − 5 × age − 161
Your TDEE, from an activity multiplier
Total daily energy expenditure is your BMR multiplied by how much you move. This is where most calculators go wrong, because most people pick the level they wish they were.
Activity multipliers used to turn BMR into TDEE Activity level Typical week Multiplier Sedentary Desk job, little or no exercise ×1.2 Lightly active Light exercise 1 to 3 days a week ×1.375 Moderately active Moderate exercise 3 to 5 days a week ×1.55 Very active Hard exercise 6 to 7 days a week ×1.725 Extra active Physical job or two training sessions a day ×1.9 Your macros, protein first
Protein is set from your body weight, not from a percentage, because your protein need scales with your body and not with how much you happen to be eating. Fat is then set as a share of your calories with a floor of 0.5 g per kg, and carbohydrate fills whatever calories are left.
- Balanced
- Steady protein, moderate fat, carbs for training. Carbs take the rest.
- Higher protein
- More protein to stay full in a deficit. Carbs take the rest.
- Lower carb
- More fat, fewer carbs, protein kept high. Carbs take the rest.
Protein and carbohydrate carry 4 calories per gram, fat carries 9. A lower carb split does not mean fewer calories, only a different shape to the same day.
Then what
What to do with these numbers
A macro target is only useful if you can see what you actually ate against it.
Write the numbers down, then track for two weeks before you change anything. If your weight is not moving the way the calculator predicted, your real maintenance is the one the scale reports, not the one the formula guessed.
Hit protein first, fat second, and let carbs float. Protein is the macro that keeps you full and protects lean mass in a deficit, and it is the one most people miss by the widest margin.
Noxy is the iPhone app that tracks the meals against these targets. Type what you ate, snap the plate or ask Siri, confirm the estimate, and the day adds itself up with protein, carbs, fat and fiber alongside the calories.
iPhone. 7-day free trial, then Noxy Pro.
How does this macro calculator work?
It estimates your basal metabolic rate with the Mifflin-St Jeor equation, multiplies it by an activity factor to get your total daily energy expenditure, then adjusts that for your goal. Protein is set from your body weight, fat is set as a share of your calories, and carbs fill whatever calories are left.
What is a good macro split for weight loss?
A common starting point in a calorie deficit is roughly 2.0 to 2.2 grams of protein per kilogram of body weight, about 25 to 30 percent of calories from fat, and carbs for the rest. Higher protein helps you stay full and holds on to lean mass while calories are low. The calorie deficit is what drives fat loss; the split mostly decides how comfortable it feels.
How much protein do I actually need?
For general health, around 0.8 grams per kilogram is the usual baseline. If you are training or eating in a deficit, most evidence supports 1.6 to 2.2 grams per kilogram of body weight per day. This calculator sits in that range and adds a little extra when your goal is fat loss.
Should I hit my macros exactly every day?
No. Landing within about 10 grams of protein and fat, and inside a sensible calorie range, is enough. Weekly averages move the scale, not any single perfect day.
How often should I recalculate my macros?
Recalculate after your weight changes by about 5 kilograms or 10 pounds, or if your training or job changes how much you move. Otherwise, adjust based on two weeks of real weight and food data rather than the formula.
Is this calculator accurate?
Mifflin-St Jeor is the equation most nutrition software uses, and it lands within about 10 percent for most people. It cannot know your body composition, so treat the output as a starting point and correct it with what the scale does over two to three weeks.
A little help along the way.
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