Carbohydrate Calculator
Pick one of three ways to get a daily carb figure. Daily target takes your age, sex, height, weight, activity level and goal, and returns your daily calories and the grams of carbs to eat. It estimates calories with the Mifflin–St Jeor equation. Protein is set at 2.2 g per kg of body weight, about 1 g per pound. Fat is 25% of calories, and carbs fill the calories left over. Per kg takes your weight and training load and gives the range from a 2016 sports nutrition position paper. By percentage takes your calories and the share you want from carbs.
How to use the Carbohydrate Calculator
- Enter your numbers in the Carbohydrate Calculator above.
- Press the Calculate Macros or Calculate button to see the result.
- To try other numbers, change any value and press the button again.
The carbohydrate calculation
Daily target: Carbs (g) = (calories − protein g × 4 − fat g × 9) ÷ 4, with Calories = Mifflin–St Jeor BMR × activity factor ± 500 · · · Per kg: Carbs (g) = kg × g per kg · · · By percentage: Carbs (g) = calories × percent ÷ 100 ÷ 4
Protein and carbs have 4 calories per gram and fat has 9. The activity factor runs from 1.2 for sedentary to 1.9 for extra active, and the goal adds or removes 500 calories. In Daily target, carbs take whatever protein and fat leave. In Per kg, a pound is 0.45359237 kg, and each training load has its range of grams per kg.
Worked example
A 28-year-old man, 5'10" and 170 lb, moderately active, with the goal set to maintain: 2,708 calories, 170 g protein and 75 g fat. Carbs = (2,708 − 170 × 4 − 75 × 9) ÷ 4 = 338 g. Per kg: a 70 kg athlete on a moderate training load of about an hour a day gets 5 to 7 g per kg, which is 350 to 490 g a day. By percentage: 50% of 2,000 calories is 2,000 × 0.5 ÷ 4 = 250 g, with the 45% to 65% range at 225 to 325 g.
Frequently asked questions
Are all carbs the same?
No. Fiber-rich whole-food carbs such as vegetables, fruit and oats digest slowly. Refined carbs and added sugars digest fast and raise blood sugar more sharply. The calculator counts grams only, so it treats both the same.
How many carbs per kg does an athlete need?
The 2016 joint position of the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine gives general daily targets by training load: 3 to 5 g per kg for light work, 5 to 7 for a moderate program of about an hour a day, 6 to 10 for 1 to 3 hours a day of endurance training, and 8 to 12 for over 4 to 5 hours a day. It says to fine-tune them to your energy needs, your training and how training goes, and that they matter less when exercise quality or intensity matters less. These are not a promise of better performance, and they are written for athletes, not for everyone.
Can I set my own carb percentage?
Yes, in By percentage. Enter your calories and the share you want from carbs, and the calculator multiplies the calories by that share and divides by 4. Half of 2,708 calories is 2,708 × 0.5 ÷ 4 = 339 g of carbs. It also shows the Acceptable Macronutrient Distribution Range of 45% to 65% of calories, which the Dietary Guidelines for Americans 2020-2025 list for adults, and says whether your share falls inside it. That range does not make a share right for you. Talk to your doctor or a dietitian before a large change, above all if you have diabetes.
Why does my carb number change with activity?
In Daily target, a higher activity level raises your calories. Protein stays where it was and fat takes 25% of the new total, so 75% of the extra calories go to carbs while carbs are above 0. Moving the man in the example from moderately active to very active takes him from 2,708 to 3,014 calories and from 338 g to 396 g of carbs.
Why does it show 0 g of carbs?
Protein and fat have used up the calories, and carbs cannot go below 0. An 80-year-old woman, 5'0" and 200 lb, sedentary, with the goal set to lose weight, gets 1,058 calories, 200 g protein and 29 g fat. Those two already come to 200 × 4 + 29 × 9 = 1,061 calories, so her grams add up to more than her calorie target.