Fiber Intake Calculator: Grams Per Day

Fiber intake calculator: how much per day

Short answer

The US adequate intake for fiber is 14 g per 1,000 kcal, which works out to 38 g a day for men and 25 g for women aged 19–50, and 30 g and 21 g from age 51. The UK recommends 30 g a day for all adults. Enter your calories to scale the US figure to what you eat.

Last reviewed 27 October 20262 published sourcesNot medical advice

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Where the targets come from

The Institute of Medicine set an adequate intake of 14 g of total fiber per 1,000 kcal, based on the intake linked to the lowest risk of coronary heart disease, then applied it to typical energy intakes by age and sex (Institute of Medicine, 2005 (macronutrients)).

The UK's Scientific Advisory Committee on Nutrition reviewed the evidence in 2015 and raised the adult recommendation to 30 g a day (SACN, 2015).

Fiber at 14 g per 1,000 kcal
Daily calories	Fiber
1,600 kcal	22 g
2,000 kcal	28 g
2,400 kcal	34 g
2,800 kcal	39 g
3,200 kcal	45 g

Daily calories

Fiber

1,600 kcal

22 g

2,000 kcal

28 g

2,400 kcal

34 g

2,800 kcal

39 g

3,200 kcal

45 g

Fitting it into your plan

Find your calories with the TDEE calculator, then split them with the macro calculator. Fiber counts toward your carbohydrate grams.

Common questions

How much fiber should I eat a day?

In the US, the adequate intake is 38 g for men and 25 g for women aged 19–50, and 30 g and 21 g from age 51; 28 g in pregnancy and 29 g while breastfeeding. The UK's Scientific Advisory Committee on Nutrition recommends 30 g a day for adults.

Why does the US figure drop after 50?

The Institute of Medicine set the adequate intake at 14 g per 1,000 kcal, so it follows typical energy intake, which is lower in older adults.

Why are the US and UK numbers different?

They were set by different committees from different evidence, and the UK's 30 g is a population average to aim for. Both are targets to build toward, not upper limits.

Sources

Figures on this page were checked against these publications on 27 October 2026.

Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005. doi.org/10.17226/10490

Scientific Advisory Committee on Nutrition. Carbohydrates and Health. London: The Stationery Office; 2015. www.gov.uk/government/publications/sacn-carbohydrates-and-health-report

Fiber intake calculator: how much per day