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Free fiber intake calculator: get how much fiber per day from Adequate Intake (age + sex) and optionally ~14 g per 1,000 kcal. See a planning anchor, food portions, and gradual ramp tips. Pair with our carbohydrate calculator for total carb context.
Last updated: May 25, 2026
Need calories first? Calorie calculator
If set, we show ~14 g fiber per 1000 kcal alongside the age-based AI.
Adequate Intake (approx.)
38 g/day
Adults 19–50 years
~14 g fiber per 1000 kcal (2200 kcal)
30.8 g/day
Planning anchor
38 g/day
AI (38 g) exceeds calorie rule (30.8 g)—AI is often the planning floor for health goals.
Not medical nutrition therapy. IBS, IBD, malabsorption, pregnancy, and medications may require different fiber strategies—ask your healthcare provider.
38 g
Age/sex AI target
30.8 g
14 × (kcal ÷ 1000)
38 g
AI (38 g) exceeds calorie rule (30.8 g)—AI is often the planning floor for health goals.
Male · 35 · 2200 kcal
AI 38 g
Female · 60 · 1800 kcal
21 g AI
Teen male · 16
38 g
Child · 7
25 g
AI (g/day) = lookup(age, sex)
Calorie line ≈ 14 × (calories ÷ 1000)
Worked: Male 35 → AI 38 g. At 2200 kcal: 14 × 2.2 = 30.8 g. Planning anchor: 38 g (AI (38 g) exceeds calorie rule (30.8 g)—AI is often the planning floor for health goals.).
| Age | Men (g/day) | Women (g/day) | Note |
|---|---|---|---|
| 1–3 years | 19 g | 19 g | Toddler AI — whole-food textures as tolerated |
| 4–8 years | 25 g | 25 g | School-age children |
| 9–13 years | 31 g | 26 g | Pre-teen growth |
| 14–18 years | 38 g | 26 g | Adolescent |
| 19–50 years | 38 g | 25 g | Adult — most cited “38 g men / 25 g women” |
| 51+ years | 30 g | 21 g | Older adult AI — slightly lower than 19–50 |
| Daily calories | Fiber (g) | vs male AI 38 g |
|---|---|---|
| 1,600 kcal | 22.4 g | -15.6 g below AI |
| 1,800 kcal | 25.2 g | -12.8 g below AI |
| 2,000 kcal | 28 g | -10.0 g below AI |
| 2,200 kcal | 30.8 g | -7.2 g below AI |
| 2,400 kcal | 33.6 g | -4.4 g below AI |
| 2,800 kcal | 39.2 g | +1.2 g above AI |
| Type | Common sources | Role |
|---|---|---|
| Soluble fiber | Oats, beans, apples, citrus, barley, psyllium | May help soften stool; feeds gut bacteria; can affect cholesterol in some diets |
| Insoluble fiber | Whole wheat, bran, nuts, cauliflower, potato skin | Adds bulk; often supports regularity when fluids are adequate |
| Total dietary fiber | Food labels list “dietary fiber” (both types combined) | This calculator targets total grams/day — not split by type |
| Food | Approx. fiber |
|---|---|
| 1 cup cooked lentils | ~15 g fiber |
| 1 cup cooked black beans | ~15 g fiber |
| 1 cup cooked oatmeal | ~4 g fiber |
| 1 medium pear (with skin) | ~5–6 g fiber |
| 1 oz almonds (~23 nuts) | ~3.5 g fiber |
| 2 tbsp chia seeds | ~10 g fiber |
| 1 cup broccoli (cooked) | ~5 g fiber |
| 2 slices whole wheat bread | ~4 g fiber |
One cup lentils (~15 g) + 1 cup broccoli (~5 g) + pear (~6 g) + oats (~4 g) ≈ 38 g/day target.
| Phase | Add ~ | Example |
|---|---|---|
| Week 1 | +3–5 g | One extra serving beans or extra vegetable at lunch |
| Week 2 | +3–5 g | Switch to whole grain bread or add berries at breakfast |
| Week 3+ | Toward AI goal | Hold at comfortable level; increase water unless restricted |
AI = 21 g/day (Adults 51+ years)
Calorie line = 14 × 1.8 = 25.2 g/day
Planning anchor: 26 g — Calorie rule (25.2 g at 1800 kcal) exceeds AI (21 g)—many planners use the higher value after clinician review.
Compare default male (35, 2,200 kcal): AI 38 g, calorie line 30.8 g, anchor 38 g.
Share it with anyone building a higher-fiber eating pattern.
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