Quick answer
A common fibre target is 14 g per 1,000 kcal. On 2,000 kcal a day that is 28 g.
Enter your daily calories. The calculator returns the fibre target. Use this fiber calculator to check your own figures.
Related tools: Calorie Calculator: Daily calories to maintain, lose or gain weight. BMR Calculator: Estimate basal metabolic rate with the Mifflin–St Jeor and revised Harris–Benedict equations. TDEE Calculator: Total daily energy expenditure from BMR and activity level.
How to use the Fiber Calculator
- Enter daily calories (kcal) (between 0 and 20000).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Daily calories | A number, in kcal | > 0, ≤ 20000 |
Formula and method
Formula
fiber = 14 g per 1,000 kcal
IEEE-754 double precision; shown to the decimals indicated.
The Institute of Medicine adequate-intake basis. Informational estimate, not medical advice. Talk to a qualified health professional about your own situation.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Daily calories = 2000.
| Result | Value |
|---|---|
| Fiber per day | 28 g |
| Basis | 14 g per 1,000 kcal |
Example 2
Inputs: Daily calories = 1850.
| Result | Value |
|---|---|
| Fiber per day | 25.9 g |
| Basis | 14 g per 1,000 kcal |
Example 3
Inputs: Daily calories = 2750.
| Result | Value |
|---|---|
| Fiber per day | 38.5 g |
| Basis | 14 g per 1,000 kcal |
The first line is the headline result (fiber per day). Below it the fiber Calculator lists basis, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
Where the figure comes from
The US Dietary Guidelines adopt 14 g per 1,000 kcal as the adequate intake. For 2,500 kcal this is 35 g. Most adults eat only about 15 g a day.
Increase gradually
Raise fibre intake gradually and drink water to avoid gas and bloating. Good sources are beans, whole grains, fruit, vegetables, nuts and seeds. Soluble and insoluble fibre both matter.
How the result changes with daily calories
Holding every other input at the first worked example, this table changes only daily calories. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Daily calories | Fiber per day | Basis |
|---|---|---|
| 1000 | 14 g | 14 g per 1,000 kcal |
| 2000 | 28 g | 14 g per 1,000 kcal |
| 4000 | 56 g | 14 g per 1,000 kcal |
| 8000 | 112 g | 14 g per 1,000 kcal |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Daily calories: entering "0" shows "Daily calories must be greater than 0." beside that field and no result.
Choosing between the Fiber Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Calorie Calculator](/health/calorie-calculator/) | units, sex and weight | Maintenance calories |
| [BMR Calculator](/health/bmr-calculator/) | units, sex and weight | Basal metabolic rate |
| [TDEE Calculator](/health/tdee-calculator/) | units, sex and weight | Total daily energy expenditure |
| [Protein Calculator](/health/protein-calculator/) | units, body weight and profile | Protein per day |
| [Macro Calculator](/health/macro-calculator/) | daily calories, carbohydrate and protein | Carbohydrate |
Background: nutrition estimates
Nutrition calculators estimate: they use population-average equations and food tables, and different tables give different numbers for the same food. Certain medical conditions change energy needs in ways basic formulas cannot see, and only laboratory analysis gives exact nutrient values.
Use the result as a starting point, track what actually happens over a few weeks and adjust; ask a qualified professional about medical or clinical decisions.
Assumptions and limitations
- Increase fiber gradually and drink water
- Not a diagnosis
This calculator gives general information based on published formulas. It is not medical advice, and it cannot account for your health history. Talk to a qualified clinician about decisions that affect your health.
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for daily calories to confirm this.
Frequently asked questions
How much fibre do I need?
About 25 g for women and 38 g for men, on average.
Does fibre have calories?
Fibre provides little usable energy: roughly 0 to 2 kcal/g, and food labels often count about 2 kcal/g.
Can I take too much?
Very high intakes can cause discomfort.
What does the Fiber Calculator calculate?
Daily fiber target from calorie intake. It returns Fiber per day and Basis.
What formula does the Fiber Calculator use?
fiber = 14 g per 1,000 kcal. The Institute of Medicine adequate-intake basis.
What do I need to enter in the fiber Calculator?
You enter Daily calories (kcal).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Increase fiber gradually and drink water.
What are the limits of this calculator?
Increase fiber gradually and drink water. Not a diagnosis.
What is an example of a fiber result?
With daily calories 2000, the fiber per day is 28 g.
Where does the method come from?
The method follows: Institute of Medicine, Dietary Reference Intakes (2005): 14 g of fiber per 1,000 kcal.
Can I rely on this calculator for a decision?
This calculator gives general information based on published formulas. It is not medical advice, and it cannot account for your health history. Talk to a qualified clinician about decisions that affect your health. For this calculator in particular: Increase fiber gradually and drink water.
Related calculators
- Calorie Calculator — Daily calories to maintain, lose or gain weight.
- BMR Calculator — Estimate basal metabolic rate with the Mifflin–St Jeor and revised Harris–Benedict equations.
- TDEE Calculator — Total daily energy expenditure from BMR and activity level.
- Protein Calculator — Daily protein target by body weight and activity.
- Macro Calculator — Split daily calories into grams of carbohydrate, protein and fat.
- Calories Burned Calculator — Estimate calories burned from activity, body weight and time using MET values.
Sources
- Institute of Medicine, Dietary Reference Intakes (2005): 14 g of fiber per 1,000 kcal
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.