acalculator

How many carbs should I eat a day?

Type your daily calories and the share of them you want from carbohydrate. The carb calculator gives grams of carbs a day and per meal, the grams at the 45% and 65% ends of the range the Dietary Guidelines give for adults, and how the total compares with the 130 g RDA.

Your numbers

The TDEE or calorie calculator can estimate this.
Carbs a day
250 g

Eat about 250 g of carbs a day (within the 45% to 65% range).

At 45% of calories
225 g
At 65% of calories
325 g
Carbs per meal
83 g
Calories from carbs
1,000
Compared with 45% to 65%
within the 45% to 65% range
Compared with the 130 g RDA
at or above 130 g

Carbs a day: 250 g. Eat about 250 g of carbs a day (within the 45% to 65% range).

This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use

How to calculate

Finds grams of carbohydrate a day from your daily calories and a carb share, with the 45% to 65% range the Dietary Guidelines give for adults, grams per meal, and the 130 g RDA.

Example with the default inputs (Calories a day 2,000, Calories from carbs 50%, Meals and snacks a day 3): Eat about 250 g of carbs a day (within the 45% to 65% range).

Method: carbs (g) = calories × share ÷ 100 ÷ 4; at 45% and 65% for the AMDR range; per meal = carbs ÷ meals. The RDA is 130 g a day.

  • Carbohydrate gives 4 calories per gram (the general factor in US nutrition labels).
  • The 45% to 65% range (AMDR) and the 130 g RDA are for healthy adults and children 1 year and older; pregnancy and breastfeeding have higher RDAs, and a doctor or dietitian may advise otherwise.
  • The page does not estimate calories; type your own figure.

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Calories a day 2,000, Calories from carbs 50%, Meals and snacks a day 3 gives Carbs a day 250 g, At 45% of calories 225 g, At 65% of calories 325 g, Carbs per meal 83 g, Calories from carbs 1,000, Compared with 45% to 65% within the 45% to 65% range.Source: Slavin J, Carlson J. Carbohydrates. Advances in Nutrition 2014;5(6):760-761 (IOM RDA for carbohydrate 130 g/d; AMDR 45–65% of total calories), https://pmc.ncbi.nlm.nih.gov/articles/PMC4224210/ (retrieved 2026-10-02); U.S. Department of Agriculture and U.S. Department of Health and Human Services, Dietary Guidelines for Americans, 2020-2025, Appendix 1 (carbohydrate: RDA 130 g a day; AMDR 45% to 65% of calories for adults), https://www.dietaryguidelines.gov/sites/default/files/2021-03/Dietary_Guidelines_for_Americans-2020-2025.pdf; 21 CFR 101.9(c)(1)(i)(C) (4 calories per gram of carbohydrate), https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/subpart-A/section-101.9
  2. Calories a day 1,800, Calories from carbs 20%, Meals and snacks a day 3 gives Carbs a day 90 g, Compared with 45% to 65% below the 45% to 65% range (low carb), Compared with the 130 g RDA 40 g below 130 g.Source: U.S. Department of Agriculture and U.S. Department of Health and Human Services, Dietary Guidelines for Americans, 2020-2025, Appendix 1 (carbohydrate: RDA 130 g a day; AMDR 45% to 65% of calories for adults), https://www.dietaryguidelines.gov/sites/default/files/2021-03/Dietary_Guidelines_for_Americans-2020-2025.pdf; 21 CFR 101.9(c)(1)(i)(C) (4 calories per gram of carbohydrate), https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/subpart-A/section-101.9
  3. Calories a day 2,600, Calories from carbs 60%, Meals and snacks a day 4 gives Carbs a day 390 g, Carbs per meal 98 g, At 65% of calories 423 g, Compared with the 130 g RDA at or above 130 g.Source: U.S. Department of Agriculture and U.S. Department of Health and Human Services, Dietary Guidelines for Americans, 2020-2025, Appendix 1 (carbohydrate: RDA 130 g a day; AMDR 45% to 65% of calories for adults), https://www.dietaryguidelines.gov/sites/default/files/2021-03/Dietary_Guidelines_for_Americans-2020-2025.pdf; 21 CFR 101.9(c)(1)(i)(C) (4 calories per gram of carbohydrate), https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-101/subpart-A/section-101.9

How it works

For C calories a day and a carbohydrate share of S percent:

  • carbs a day (g) = C × S ÷ 100 ÷ 4, because carbohydrate gives 4 calories per gram
  • calories from carbs = C × S ÷ 100
  • at the ends of the adult range (AMDR): C × 45 ÷ 100 ÷ 4 g and C × 65 ÷ 100 ÷ 4 g
  • carbs per meal = carbs a day ÷ meals and snacks
  • compared with 45% to 65%: "below the 45% to 65% range (low carb)" when S < 45, "above the 45% to 65% range" when S > 65, otherwise "within the 45% to 65% range" (45 and 65 are within)
  • compared with the 130 g RDA: "at or above 130 g" when carbs a day ≥ 130, otherwise "D g below 130 g", where D = 130 − carbs rounded to a whole gram (halves up)

The maths runs in double precision.

Rules

  • Calories a day are 500 to 10,000. The share is 0% to 100%. Meals and snacks are a whole number from 1 to 12.
  • The range and the RDA are for healthy adults (the RDA also for children 1 year and older); pregnancy, breastfeeding, diabetes and other conditions have their own advice.

Output format. Grams and calories to whole numbers.

Worked examples by hand

2,000 calories at 50%, 3 meals. 2,000 × 0.50 = 1,000 calories ÷ 4 = 250 g a day, 83 g a meal. Range: 2,000 × 0.45 ÷ 4 = 225 g to 2,000 × 0.65 ÷ 4 = 325 g; 50% is within it.

1,800 calories at 20%. 1,800 × 0.20 ÷ 4 = 90 g: below the range (low carb), and 130 − 90 = 40 g below 130 g.

2,600 calories at 60%, 4 meals. 2,600 × 0.60 ÷ 4 = 390 g a day, 390 ÷ 4 = 97.5 g a meal; at 65% it would be 422.5 g; at or above 130 g.

Other questions people ask

How many carbs should I eat a day?

The Dietary Guidelines for Americans give adults a range of 45% to 65% of calories from carbohydrate. On 2,000 calories a day, that is 2,000 × 0.45 ÷ 4 = 225 g to 2,000 × 0.65 ÷ 4 = 325 g of carbs.

How do I turn a carb percentage into grams?

Multiply your calories by the percentage, then divide by 4, because a gram of carbohydrate gives 4 calories. 50% of 2,000 calories is 1,000 calories, or 1,000 ÷ 4 = 250 g.

What is the RDA for carbohydrate?

130 g a day for adults and children 1 year and older, set by the Institute of Medicine as the amount of glucose the brain needs. Pregnancy and breastfeeding have higher RDAs. Most people eat well above it.

How many carbs are low carb?

There is no single official cut-off. A share below 45% of calories is below the AMDR range, and the page labels it low carb. At 20% of 1,800 calories, carbs are 90 g a day, 40 g below the RDA. Talk to a doctor or dietitian before a very low-carb diet.

How many carbs per meal?

Divide carbs a day by how many times you eat. 250 g over 3 meals is about 83 g a meal; 390 g over 4 meals and snacks is 97.5 g each.

Where do my daily calories come from?

Type the calories you eat or plan to eat. If you do not know them, a TDEE or calorie calculator estimates them from your body and activity, and the macro calculator splits them into protein, carbs and fat.