Daily Fiber Target

Adults: 25 g women / 38 g men. Most US adults get half that.

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How to use this calculator

  • Pick sex + age.

About this calculator

Fiber recommendations: men <50: 38 g; women <50: 25 g; both drop ~20% after 50. Most US adults get ~16 g/day — about half target. Soluble fiber (oats, beans, apples) lowers cholesterol; insoluble (whole grains, vegetables) helps regularity. Both improve satiety and gut microbiome diversity. Source: Institute of Medicine 2005 DRI.

Frequently asked

Why drop after 50?+
Lower caloric needs at older ages → proportionally less fiber needed. Same 14 g/1000 kcal rule.
Symptoms of low fiber?+
Constipation, blood sugar spikes, hunger between meals, less microbiome diversity.
Too much fiber?+
Above 50g/day can cause gas, bloating. Increase gradually + drink more water.
Fiber supplements?+
Inulin, psyllium husk (Metamucil), wheat dextrin (Benefiber). Less ideal than whole foods but helpful.
Soluble vs insoluble?+
Soluble dissolves in water (oats, beans) — slows digestion, lowers LDL. Insoluble (wheat bran, veggies) — adds bulk.

Related calculators

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Daily Sodium Target
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Caffeine Half-Life Clearance
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Fiber Per Serving Calculator
Total fiber / servings. Compare to FDA daily reference (25 g women, 38 g men).
Rest Day / Recovery Calculator
Recommended rest days = base + intensity adjustment − sleep credit + age adjustment.

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