Stop guessing what to put on your plate.Get the exact protein, carbs, and fat to eat today.
"Eat better" is not a plan. Enter a few stats and you get the exact grams of protein, carbs, and fat to eat each day - and per meal - to lose fat, hold steady, or build lean muscle. Thirty seconds, no signup.
How a macro calculator works
Your macros are the daily grams of protein, carbohydrate, and fat that make up your calories. To calculate them in three steps: (1) set a daily calorie target - your maintenance calories (Mifflin-St Jeor BMR multiplied by an activity factor of 1.2 to 1.9), adjusted about 20% lower to lose fat or about 12% higher to build muscle; (2) set protein at roughly 1 gram per pound of bodyweight (4 calories per gram); (3) set fat at about 0.25 to 0.35 grams per pound (9 calories per gram) and fill the remaining calories with carbohydrates (4 calories per gram). For example, a 185-pound person eating 2,200 calories per day would aim for about 185 grams of protein, 60 to 70 grams of fat, and 215 to 230 grams of carbohydrate - the protein and fat are fixed first, and carbohydrate takes whatever calories remain.
Macros - short for macronutrients - are the three nutrients that supply all of your calories: protein, carbohydrate, and fat. A macro calculator turns a daily calorie target into the grams of each one to eat. Calories decide whether you lose, hold, or gain weight; macros decide how good you feel and whether the weight you change is fat or muscle.
The math runs in three steps. First, set calories. You can enter a target you already follow, or compute it: your basal metabolic rate (the calories you burn at rest) is estimated from your sex, age, height, and weight with the Mifflin-St Jeor equation, multiplied by an activity factor (1.2 for a desk day up to 1.9 for an athlete) to get maintenance, then adjusted for your goal - about 20% below maintenance to lose fat, or roughly 12% above for a lean bulk.
Second, set protein. Protein is anchored to your bodyweight - about 1 gram per pound - because that is what protects muscle while you diet and supports building it in a surplus. At 4 calories per gram, that protein claims its share of the day's calories. Third, set fat from your diet style, keeping at least roughly 0.3 grams per pound for hormone and cell health (fat is 9 calories per gram). Whatever calories remain go to carbs at 4 calories per gram. Balanced, high-protein, low-carb, and keto are just different ways of dividing those remaining calories between carbs and fat.
Treat the output as a starting line, not gospel. A calculator lands within about 5 to 10% of your true needs, but metabolism, hormones, and daily movement vary person to person. Follow the targets for two to three weeks, watch your weight trend, and adjust calories up or down based on what actually happens on the scale.
Common questions
How do you calculate your macros?
Calculating macros is a three-step process. First, set a daily calorie target - either from your maintenance calories (your body's daily burn, estimated with the Mifflin-St Jeor equation and an activity factor) adjusted for your goal, or a number you already follow. Second, set protein: about 1 gram per pound of bodyweight to protect muscle, which works out to 4 calories per gram. Third, set fat from your diet style (keeping at least 0.3 grams per pound for hormone health at 9 calories per gram) and fill the rest of your calories with carbs at 4 calories per gram. This calculator runs all three steps for you and shows the grams of protein, carbs, and fat to hit every day.
What macros should I eat to lose weight?
To lose weight, eat in a calorie deficit (about 20% below maintenance is a sustainable pace) while keeping protein high - around 1 gram per pound of bodyweight - so the weight you lose comes from fat, not muscle. A common fat-loss split is roughly 40% protein, 35% carbs, and 25% fat, but the protein target matters far more than the exact carb-to-fat ratio. Pick the carb and fat balance you can actually stick to. This tool builds the deficit and the high-protein split automatically when you choose the lose-fat goal.
How much protein should I eat per day?
For body composition, aim for about 0.7 to 1 gram of protein per pound of bodyweight per day - so roughly 130 to 185 grams for a 185-pound person. The higher end (1 gram per pound) is most useful when you are in a calorie deficit and trying to keep muscle, or when building muscle in a surplus. The ISSN position stand supports 1.4 to 2.0 grams per kilogram (about 0.6 to 0.9 grams per pound) for active people, going higher during a diet. This calculator anchors your protein to your bodyweight first, then fills the rest of your calories with carbs and fat.
What is the best macro split for fat loss?
There is no single best macro split - the deficit and your protein intake drive fat loss, and the carb-to-fat balance is mostly preference. A high-protein split (around 40% protein, 35% carbs, 25% fat) tends to preserve the most muscle and keeps you full. Some people lose fat more easily on lower carbs (a low-carb or keto split shifts those calories to fat). The split you can sustain for months beats the theoretically optimal one you quit in a week. This tool lets you compare balanced, high-protein, low-carb, and keto splits for the same calorie target.
Are macro calculators accurate?
A macro calculator gives a solid starting estimate, usually within 5 to 10% of your true needs. It cannot measure your exact metabolism, hormones, or how much you actually move outside of exercise, so treat the numbers as a starting line, not a verdict. The accurate way to use it: follow the targets for two to three weeks, track your weight trend, and adjust calories up or down based on what the scale actually does. If your numbers are dialed in and the scale still will not move, an underlying metabolic or hormonal factor may be worth a clinician's review.