How much fiber you need each day — from age and sex, or from your calories — and how far your current intake falls short.
If given, the target is 14 g per 1,000 kcal instead of the age/sex table.
How to use this tool
The standard tables give different targets for men and women, and lower targets after age 50.
If you know your calorie intake, the 14 g per 1,000 kcal rule gives a personalised target instead.
Under Advanced options, enter your current daily fiber to see your gap and the share of target met.
Beans, lentils, oats, whole grains and fruit with the skin on are the easiest wins — raise intake slowly and drink water.
Formula & worked example
Worked example: a 30-year-old woman eating 2,000 kcal a day has a calorie-based target of 14 × 2 = 28 g. The table would give 25 g. If she currently eats 15 g, her gap is 13 g — roughly a cup of lentils or three apples with skin.
Limitations — read this before you rely on it
These are general population recommendations (US Institute of Medicine / Dietary Guidelines style figures), not personal medical advice. People with bowel conditions, on restricted diets, or with medical conditions should follow their clinician's guidance, and fiber should rise gradually to avoid discomfort.
Frequently asked questions
Most adults need 25–38 g a day: women 25 g up to age 50 and 21 g after, men 38 g up to 50 and 30 g after. By calories, the rule is 14 g per 1,000 kcal — 28 g on a 2,000 kcal diet.
Soluble fiber (oats, beans, apples) dissolves into a gel and helps cholesterol and blood sugar. Insoluble fiber (whole wheat, vegetables) adds bulk and keeps digestion moving. You need both — roughly a quarter soluble, three quarters insoluble.
Lentils and beans (about 15 g per cooked cup), raspberries, pears and apples with skin, oats, chia and flax seeds, and whole-grain breads. A single high-fiber food rarely closes a big gap alone — spread it across meals.
Very high intakes (above 50–70 g) can cause bloating and gas, especially if raised suddenly, and can interfere with mineral absorption. Increase gradually over a couple of weeks and drink enough water.
It helps indirectly: high-fiber foods are filling for their calories, slow eating and steady blood sugar, which makes it easier to stay full on fewer calories. It is not a fat-burner on its own.