Daily Fiber Intake Calculator
Estimate your recommended daily fiber target in grams by age and sex, or from your calorie intake.
This is an educational estimate, not medical advice. Everything runs entirely in your browser and nothing is uploaded.
How to use this tool
- Pick a mode. Use "By age and sex" for the standard guideline target, or "By calories" if you track your daily calories.
- For the first mode, choose your sex and enter your age in years.
- For the calorie mode, type the number of calories you eat on a typical day.
- Click Calculate to see your recommended daily fiber intake in grams.
- Use Copy result to save the number for your notes or a food log.
The result is a daily target. You do not need to hit it in a single meal, just spread fiber-rich foods across the day.
How it works
There are two common ways to set a dietary fiber target in grams. The simplest is a flat recommendation based on age and sex, drawn from widely used dietary guidelines. The other scales fiber to how much you eat, using roughly 14 grams of fiber for every 1,000 calories.
For ages 4 to 8 the same target applies to both sexes, and for ages 1 to 3 it is the same as well. The calorie method is handy because a larger, more active person eats more food and therefore needs more fiber.
A real example
Say you are a 35-year-old woman. Using the age and sex table, your daily fiber target is about 25 grams. Now switch to the calorie method and assume you eat 2,000 calories a day: 2,000 divided by 1,000 is 2, multiplied by 14 gives 28 grams. The two methods land close together, which is expected, and either makes a reasonable goal to aim for.
Common questions
How much fiber should I eat per day?
Most adults do well on roughly 25 to 38 grams of dietary fiber per day, with men needing more than women and the target dropping a little after age 50. Use the age and sex table above for a quick recommended figure.
Why does the recommended fiber differ by age and sex?
Larger bodies and higher calorie needs generally call for more fiber, so adult men have a higher target than women, and younger active teens are near the top of the range. Needs taper down later in life as calorie intake tends to fall.
What is the 14 grams per 1,000 calories rule?
It is a guideline that ties your dietary fiber target to how much you eat. Multiply your daily calories by 14 and divide by 1,000 to get fiber in grams. It is useful if you already count calories and want a personalized number.
Can I get too much fiber?
Going well above your target quickly, especially without enough water, can cause bloating, gas, or cramping. Increase fiber gradually over a couple of weeks and drink plenty of fluids so your body adjusts comfortably.
Is this calculator medical advice?
No. It gives an educational estimate based on general dietary guidelines. If you have a medical condition, are pregnant, or follow a special diet, talk with a doctor or registered dietitian for personalized advice.