Carbohydrate calculator
How many grams of carbs to eat a day for your calories and goal.
About this calculator
How many carbs should I eat a day? This carbohydrate calculator estimates your daily calories from your age, sex, size and activity, then turns the recommended share into grams.
It also gives a fibre goal, a limit for added sugar and a table of carbs at different shares, from low carb to high carb.
How it works
Works out your daily calories with the Mifflin-St Jeor equation and your activity, adjusted for your goal. Carbohydrates have 4 kcal per gram, so grams = calories × share ÷ 4. The usual range for adults is 45% to 65% of calories.
Last reviewed:
Worked example
- Units: Feet and pounds
- Sex: Female
- Age: 35 years
- Height: 5 ft 7 in
- Weight: 155 lb
- Activity: Light exercise, 1 to 3 days a week
- Goal: Maintain
Carbohydrates a day: 221–320 g (45% to 65% of your calories)
Common questions
How many carbs should I eat a day?
For most adults, 45% to 65% of calories. On 2,000 kcal a day, that is 225 to 325 g.
How many carbs a day is low carb?
Usually below about 26% of calories, often under 130 g a day. Very low-carb diets such as keto go below 50 g.
How much fibre should I eat?
About 14 g for every 1,000 kcal, or roughly 25 g a day for women and 38 g for men, according to US guidelines.
Sources and further reading
The story behind it
Where the idea came from: The US Institute of Medicine set the 45% to 65% range for carbohydrates in 2002, in its Dietary Reference Intakes for energy and macronutrients.
The range is wide on purpose: healthy diets from many cultures fall inside it. The quality of the carbs, such as whole grains, fruit and vegetables rather than added sugar, matters as much as the amount.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, not medical advice.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
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