How your macros are calculated
First the calculator estimates the calories you burn in a day. It uses the Mifflin-St Jeor equation for your resting burn (BMR), multiplies by your activity level to get your total daily energy expenditure (TDEE), then adds or takes away calories for your goal. That total is split into protein, carbs and fat by the percentages you choose, and each is turned into grams.
Protein and carbohydrates have about 4 calories per gram, and fat about 9.
Example: a 30-year-old man, 5 ft 9 in (175 cm) and 165 lb (75 kg), who exercises 3 to 5 days a week, has a BMR of 1,699 and a TDEE of 2,633 calories. On a balanced 30/40/30 split to maintain weight, that's 197 g of protein, 263 g of carbs and 88 g of fat a day. Over 3 meals, about 66 g protein, 88 g carbs and 29 g fat each.
Which macro split should I use?
| Split | Protein / Carbs / Fat | Good for |
|---|---|---|
| Balanced | 30 / 40 / 30 | A sensible default for most people |
| High protein | 40 / 35 / 25 | Losing fat while keeping muscle, staying full |
| Low carb | 35 / 25 / 40 | People who feel better with fewer carbs |
| Keto | 25 / 5 / 70 | Ketogenic diets, usually under about 50 g of carbs |
| Endurance | 20 / 55 / 25 | Runners, cyclists and long training sessions |
The Institute of Medicine's healthy ranges for adults are 10–35% protein, 45–65% carbs and 20–35% fat. Higher-protein and lower-carb splits fall outside those ranges by design, and many people use them successfully. The best split is one you can keep eating day after day.
Protein first
For active people, research points to about 1.4 to 2.0 g of protein per kg of body weight a day (0.6 to 0.9 g per lb), and up to about 2.2 g per kg when losing fat. The calculator shows your protein per pound and per kilogram so you can check your split lands in that range.
These are estimates to start from. Weigh yourself regularly for two to three weeks and adjust calories by 100 to 200 a day if you're not moving toward your goal. If you have a medical condition, are pregnant or have a history of disordered eating, work with a doctor or registered dietitian instead.
Frequently asked questions
How do I calculate my macros?
Find your daily calories (BMR × activity level, plus or minus your goal), choose a split such as 30% protein, 40% carbs and 30% fat, then divide each share of calories by 4 for protein and carbs or by 9 for fat to get grams.
How many grams of protein do I need a day?
For active adults, about 0.6 to 1 g per pound of body weight (1.4 to 2.2 g per kg). The minimum for sedentary adults is 0.8 g per kg, about 0.36 g per pound.
What macros should I eat to lose weight?
Eat fewer calories than you burn, and keep protein high, around 0.7 to 1 g per pound, to hold on to muscle. The high-protein split with a 500-calorie deficit is a common starting point.
Is this the same as my calorie needs?
The daily calories here match the calorie calculator, with your goal added. This page then splits those calories into protein, carbs and fat.
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