Fiber Calculator Formula

Understand the math behind the fiber calculator. Each variable explained with a worked example.

Use the Fiber Calculator

Formulas Used

Dietary Fiber

fiber_g = food_weight_g * fiber_pct / 100

% of 28 g Daily Value

pct_daily_28g = (food_weight_g * fiber_pct / 100) / 28 * 100

Variables

VariableDescriptionDefault
food_weight_gFood Weight(g)100
fiber_pctFiber Content7

How It Works

How to Calculate Fiber Content

Formula

Fiber (g) = Food Weight (g) x Fiber Percentage / 100

Daily Recommendations

  • Women: 25 g per day
  • Men: 38 g per day
  • FDA Daily Value: 28 g

    • High-Fiber Foods

  • Chia seeds: 34 g per 100 g
  • Lentils: 7 g per 100 g cooked
  • Oats: 10 g per 100 g dry

    • Worked Example

    Calculate fiber in 100 g of cooked lentils.

    food_weight_g = 100fiber_pct = 7
    1. 01Lentil fiber content: 7 g per 100 g cooked.
    2. 02Fiber: 100 x 7/100 = 7 g.
    3. 03% of daily value: (7/28) x 100 = 25%.

    Frequently Asked Questions

    What are the types of fiber?

    Soluble fiber (dissolves in water, found in oats, beans) helps lower cholesterol. Insoluble fiber (found in whole grains, vegetables) aids digestion. Both are important.

    Does fiber have calories?

    Fiber provides about 2 kcal per gram (less than other carbs) because it is only partially fermented in the gut.

    Can I eat too much fiber?

    Yes, excessive fiber (over 70 g/day) can cause bloating and gas. Increase intake gradually and drink plenty of water.

    Ready to run the numbers?

    Open Fiber Calculator