Fiber Calculator
An Intake Target Most People Fall Well Short Of
Fiber recommendations are set by age and sex through the Institute of Medicine's Dietary Reference Intake tables, the same framework used for vitamins and minerals. Actual average intake across most Western populations lands well below these targets, which is part of why fiber gets called out specifically rather than assumed to come along automatically with a balanced diet.
Recommended Daily Fiber Intake
| Age group | Male | Female |
|---|---|---|
| Up to 3 years | 19 g/day | 19 g/day |
| 4 – 8 years | 25 g/day | 25 g/day |
| 9 – 13 years | 31 g/day | 26 g/day |
| 14 – 18 years | 38 g/day | 26 g/day |
| 19 – 50 years | 38 g/day | 25 g/day |
| 51+ years | 30 g/day | 21 g/day |
An Alternative Calorie-Based Estimate
Calorie-Based Fiber Estimate (g) = (Daily Calories ÷ 1000) × 14
This alternative rule of thumb — 14 grams of fiber per 1,000 calories consumed — is available in this calculator as a cross-check when a daily calorie figure is entered alongside age and gender.
Why Fiber Intake Is Tracked Specifically
- Digestive health — fiber is central to regular bowel function and is one of the most consistently under-consumed nutrients in modern diets.
- Cardiovascular and metabolic health — higher fiber intake is associated with better cholesterol and blood sugar management in population-level studies.
- Age-based targets decrease later in life — the recommended amount for adults over 50 is lower than for younger adults, reflecting typically lower calorie needs at older ages.
How to Use This Calculator
- Enter your age.
- Select your gender.
- Optionally enter your daily calorie intake for an alternative calorie-based estimate.
- Select Calculate to see your recommended daily fiber intake.
Related Calculations
Fiber is a subcategory of total carbohydrate intake — see the Carbs Calculator for your overall carbohydrate target.