Fiber Intake Calculator
See how much dietary fiber you should eat per day — both as a general recommendation and a personal estimate based on your own energy needs.
How to use the calculator
- Choose gender.
- Enter your daily energy needs if you know them (e.g. from the calorie calculator) — otherwise only the general guideline is shown.
- See your recommended daily fiber intake.
How it's calculated
The Nordic Nutrition Recommendations 2023 recommend at least 3 grams of dietary fiber per megajoule (MJ) of energy intake for adults. Based on reference energy values, this corresponds to at least 25 g/day for women and 35 g/day for men. The calculator also shows a more personalized estimate by applying the 3 g/MJ rule directly to your own stated energy needs.
Soluble and insoluble fibre do different jobs
Dietary fibre is not a single substance but a collective term. Insoluble fibre — from wholegrains, skins and vegetables — binds water and adds bulk, which supports regular transit. Soluble fibre, found in oats, legumes and many fruits, forms a gel-like mass that among other things affects how quickly carbohydrates are absorbed, and is the type associated with effects on cholesterol.
Most dietary guidelines give a single combined figure, but a varied source is the point behind that number. If you increase fibre intake abruptly, bloating in the first few weeks is common — digestion copes better with a gradual increase. Fibre also needs fluid to work as intended, so a high fibre intake without enough to drink can have the opposite of the desired effect.
Frequently asked questions
What is dietary fiber?
Dietary fiber is the part of plant food the body doesn't fully break down — found in whole grains, legumes, vegetables, fruit, and nuts, and it supports digestion and satiety.
Why is the recommendation different for women and men?
Because the recommendation is tied to energy intake (3 g per MJ), and men have a higher average reference energy requirement than women.
Why might another guideline give a different number?
Official fiber targets vary somewhat by country and may use a fixed daily amount or a value per 1,000 kcal. This calculator consistently follows the Nordic Nutrition Recommendations 2023.