Fiber Calculator — Daily Dietary Fiber Intake
Find out how much dietary fiber you should eat per day based on your age and sex, see how your current intake compares, and discover high-fiber foods to help you reach your goal.
years
Sex
kcal
g
You are 20 g/day below the recommendation
- 1
Calories per 1,000 kcal unit
2,000 ÷ 1000 = 2 - 2
Calorie-based fiber estimate
2 × 14 = 28 g/dayThe DRI fiber target is derived from 14 g per 1,000 kcal consumed.
How does this calculator work?
Recommended fiber: 38 g/day (men 19–50), 25 g/day (women 19–50), or 14 g per 1,000 kcal consumed. Most Western adults consume only 10–15 g/day. Enter your age, sex, and calorie intake to get a personalised target, and compare it to your current intake.
Formula
How this is calculated
Dietary fiber recommendations come from the Dietary Reference Intakes (DRI) published by the Institute of Medicine and adopted by the USDA Dietary Guidelines for Americans (2020–2025). The reference values are based on observed dietary patterns associated with reduced risk of coronary heart disease. Men aged 19–50 need 38 g/day, dropping to 30 g/day after 50; women aged 19–50 need 25 g/day, dropping to 21 g/day after 50. Children and adolescents have their own targets, shown in the table built into this calculator.
The alternative calorie-based rule — 14 grams of fiber per 1,000 kcal consumed — is the basis on which the DRI targets were derived and is useful as a sanity check: it aligns closely with the age/sex tables for typical adult calorie intakes. This calculator shows both figures. If your calorie intake differs substantially from the average assumed in the age/sex table (about 2,000–2,600 kcal/day for most adults), the calorie-based estimate may be more personalized.
The fraction bar shows your current intake against your recommended intake at a glance. Most adults in Western countries consume only 10–15 g/day — well below the target. Fiber is found in whole grains, legumes, fruits, vegetables, nuts and seeds. Both soluble fiber (oats, legumes, fruit) and insoluble fiber (wheat bran, vegetables) contribute to the daily total.
Frequently asked questions
Yes — very high intakes (above 70 g/day) can cause bloating, gas, and reduce absorption of minerals such as calcium, zinc, and iron. There is no established Tolerable Upper Intake Level for fiber, but most health authorities advise increasing intake gradually with plenty of water to minimise digestive discomfort.
Fiber supplements (psyllium, inulin, methylcellulose) do count toward the daily total, but whole-food sources provide additional vitamins, minerals, antioxidants, and phytonutrients not present in supplements. The recommendation is to meet fiber needs primarily from whole foods.
Soluble fiber dissolves in water to form a gel, slowing digestion and helping lower LDL cholesterol (found in oats, barley, legumes, apples, citrus). Insoluble fiber adds bulk and speeds movement through the colon, promoting regularity (found in wheat bran, wholegrains, vegetables). Most fiber-containing foods provide a mixture of both types.
Also known as
TG we-Calculate Editorial Team. (2026). Fiber Calculator — Daily Dietary Fiber Intake [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/fiber-calculator
TG we-Calculate Editorial Team. "Fiber Calculator — Daily Dietary Fiber Intake." TG we-Calculate. 2026. https://we-calculate.com/calculator/fiber-calculator.
TG we-Calculate Editorial Team, "Fiber Calculator — Daily Dietary Fiber Intake," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/fiber-calculator
@misc{wecalculate_fiber_calculator, title = {Fiber Calculator — Daily Dietary Fiber Intake}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/fiber-calculator}}, year = {2026}, note = {TG we-Calculate} }
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