Uniform Distribution Probability Calculator

Enter bounds, choose type, and inspect exact results. Compare density, mean, variance, percentiles, and intervals. Export clean reports for statistics work, lessons, and review.

Calculator Form

Formula Used

For a continuous uniform distribution from a to b:

How to Use This Calculator

  1. Enter the lower bound and upper bound.
  2. Select the probability or measure you want.
  3. Enter x, x1, x2, or p when needed.
  4. Choose decimal places for rounding.
  5. Press Calculate to view the result below the header.
  6. Use CSV or PDF buttons to save the output.

Example Data Table

Lower a Upper b Question Input Expected Result
0 10 P(2 ≤ X ≤ 8) x1 = 2, x2 = 8 0.600000
5 15 P(X ≤ 9) x = 9 0.400000
20 40 Q(0.75) p = 0.75 35.000000
-3 3 Mean a = -3, b = 3 0.000000

Understanding Uniform Distribution Probability

A uniform distribution describes a random value spread evenly across a fixed interval. Every equal length inside the interval has the same chance. This makes the model simple, fair, and useful for many statistics lessons.

What This Calculator Does

This calculator finds probabilities for continuous uniform distributions. You enter a lower bound and an upper bound. Then you choose a probability question. The tool can evaluate left tail, right tail, between values, outside values, density, point probability, and quantiles. It also reports mean, median, variance, and standard deviation.

Why the Bounds Matter

The lower and upper bounds define the full possible range. Values below the lower bound have zero cumulative probability. Values above the upper bound have full cumulative probability. Values inside the interval rise in a straight line. Because the density is constant, probability depends only on interval length.

Practical Uses

Uniform models appear when outcomes are equally likely inside limits. They are common in random number generation, waiting time approximations, simulation inputs, quality checks, and classroom examples. The model also helps compare simple continuous probability with more complex distributions.

Interpreting the Result

For a between calculation, the answer is the overlap length divided by the total distribution length. For a left tail calculation, the answer is the cumulative probability at the selected value. For a right tail calculation, the answer is one minus the cumulative probability. A single exact value has probability zero in a continuous model.

Accuracy Notes

The calculator clips interval requests to the valid distribution range. This prevents impossible negative probabilities. It also accepts reversed interval inputs and sorts them before calculation. Decimal control helps you prepare rounded answers for homework, reports, or quick checks.

Export Options

Use CSV export when you need spreadsheet data. Use PDF export when you need a clean summary. Both exports include key inputs, probability results, and distribution measures. These options make the calculator useful for repeated practice and documentation.

Best Practice

Always confirm the lower bound is smaller than the upper bound. Choose the probability type that matches your question. Review the formula section before using exported results. This habit reduces mistakes and improves statistical understanding. Save examples to compare future probability questions with confidence.

FAQs

What is a uniform distribution?

It is a probability model where every equal interval inside the range has the same chance. The distribution is defined by a lower bound and an upper bound.

What does the lower bound mean?

The lower bound is the smallest possible value in the distribution. Any value below it has zero probability density and zero cumulative probability.

What does the upper bound mean?

The upper bound is the largest possible value in the distribution. Any value above it has full cumulative probability and zero density.

Why is exact point probability zero?

A continuous distribution spreads probability over intervals, not single points. So P(X = x) is zero, even when x lies inside the range.

How is between probability calculated?

The calculator finds the valid overlap length between your interval and the distribution range. It divides that length by the total range length.

Can x1 be greater than x2?

Yes. The calculator sorts the two interval values before calculating. This prevents reversed inputs from producing an invalid probability.

What is the density value?

Density is 1 divided by the range length. It stays constant for all values between the lower and upper bounds.

What is a quantile?

A quantile is the value below which a chosen probability lies. For example, Q(0.75) gives the third quartile of the distribution.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.