Random Number Generator

Enter the Minimum and Maximum values for the range. The generator includes both endpoints when they are valid values on the selected grid.

Select Generate number to create one result using the default settings.

Open Generation options to change the result count, decimal precision, sort order, or duplicate policy. The collapsed summary shows the active settings without requiring the panel to remain open.

After generation, use Again to create a new result with the same settings, Copy to copy one number per line, or Download to save the values in a text file.

The minimum and maximum define the complete permitted interval. A range from 1 to 100 can return any whole number from 1 through 100, including both 1 and 100.

Negative values and ranges crossing zero are supported. For example, -5 through 5 contains 11 integers: five negative numbers, zero, and five positive numbers.

The order in which the bounds are entered matters. The minimum must be less than or equal to the maximum.

When the minimum and maximum are equal, the range contains one eligible value and every valid draw returns that value.

Set decimal places to 0 to generate integers. Every safe integer between the minimum and maximum is eligible.

Choose between 1 and 6 decimal places to generate values from a fixed decimal grid. Two decimal places produce steps of 0.01, three produce steps of 0.001, and six produce steps of 0.000001.

Decimal generation does not create an arbitrary floating-point number and round it afterward. The generator first identifies the valid grid positions and then selects one of those positions.

This approach gives every displayed fixed-precision value one defined position in the eligible pool.

The generator scales the entered range by 10 raised to the selected number of decimal places. It then works with integer tick positions rather than repeatedly performing decimal arithmetic.

For two decimal places, 1.25 is represented by tick 125 and 1.30 by tick 130. The eligible ticks are 125, 126, 127, 128, 129, and 130.

When a boundary lies between grid positions, the grid moves inward. A minimum of 1.123 with two decimal places begins at 1.13 rather than 1.12 because 1.12 is below the entered minimum.

The interface shows the actual first value, last value, step, and number of eligible values before generation.

A selected precision permits only certain values. At two decimal places, values occur in hundredth steps; 1.123 is not one of those values.

The lower boundary moves upward to the first valid grid value inside the range. The upper boundary moves downward to the final valid grid value inside the range.

For a range from 1.123 to 1.138 at two decimal places, the only eligible value is 1.13.

This is different from rounding the entered boundaries. The generator never adds a value that lies outside the original range.

Open Generation options and enter a count from 1 through 1,000.

When repeated values are allowed, each draw uses the complete eligible pool. The same number can therefore appear more than once in the result.

The result panel displays generated values in a compact scrollable grid. Copying or downloading places one formatted number on each line.

The requested count affects how many draws are made, not the probability assigned to each eligible value on an individual draw.

Enable Unique values to select without replacement. Once an eligible value has been selected, it cannot appear again in the same generated result.

The count cannot exceed the eligible pool. A range from 1 through 5 can produce at most five unique integers.

Unique generation applies only to the current result. Selecting Generate again starts a new sample from the full configured range.

The implementation uses sparse partial Fisher–Yates sampling. Memory use grows with the requested count rather than with the complete eligible range.

Choose Generated order when the sequence of draws matters. This preserves the first, second, and later generated positions.

Choose Ascending or Descending to reorder the completed result numerically.

Sorting happens after every number has been selected. It does not change the eligible range, selection probabilities, duplicate policy, or generated set.

Do not sort a unique result when the purpose is to create a randomized order. Sorting would retain the values but remove the randomized sequence.

When the eligible pool contains n values, each value has a theoretical probability of 1 divided by n on one draw.

A range from 1 through 100 contains 100 eligible integers, so each integer has a 1% chance on an individual draw.

With repeats allowed, each draw is independent and uses the complete pool again.

When k unique values are selected without replacement from n eligible values, each eligible value has a k divided by n probability of appearing somewhere in the completed sample.

Random does not mean that every result will appear evenly over a short sequence.

When repeats are allowed, the same value can appear several times in succession even when every eligible value has equal probability.

A number that has not appeared recently is not due to appear. Previous independent draws do not change its probability on the next draw.

Enable Unique values when the task specifically requires every number in the current result to be different.

The generator obtains random integer values through Crypto.getRandomValues(), the browser interface for cryptographically strong random values.

Those source values must still be mapped to the requested range. A simple remainder operation can introduce bias when the source range is not evenly divisible by the target pool size.

The shared random-number helpers use rejection sampling to discard the small leftover region before mapping a source value to an eligible index.

For pools larger than 2^32 values, the implementation uses a 53-bit sampler while remaining within JavaScript's supported integer precision.

JavaScript uses the IEEE 754 double-precision number format. It cannot represent every integer exactly once values move outside the safe-integer range.

Integer mode therefore requires both boundaries to be safe integers. Decimal mode applies the same requirement after the values are scaled into integer ticks.

Rejecting unsupported ranges prevents distinct mathematical values from collapsing into the same stored JavaScript number.

A rejected range should be reduced in magnitude, widened when no decimal grid point exists, or generated using fewer decimal places.

The Copy action places every generated value on a separate line, making the result easy to paste into a spreadsheet, document, code editor, or form.

The Download action creates a plain-text file named random-numbers.txt in the browser.

Fixed-decimal results preserve the selected number of decimal places. A value mathematically equal to 2.5 is exported as 2.50 when two decimal places are selected.

Downloaded and copied values contain the numbers only; interface labels and explanatory text are not included.

The generator is useful for classroom activities, games, demonstrations, randomized ordering, software test data, examples, and informal number selection.

Although the browser source provides cryptographically strong random values, this general interface does not enforce the formats, entropy requirements, lifecycle controls, or secure handling needed for passwords and cryptographic secrets.

The tool does not provide participant verification, seeded reproducibility, signed records, public audit logs, independent witnessing, or regulatory controls.

Use a purpose-built and appropriately reviewed system for security credentials, regulated drawings, valuable prizes, formal experiments, medical allocation, or other high-stakes decisions.

Range settings and generated results are processed in the browser. They do not need to be uploaded to a server.

The values are not placed in the page URL and are not permanently saved by the generator.

Copying places the result on the system clipboard, where it may be visible to other applications with clipboard access.

Downloading creates a local text file through the browser. The user controls where that file is stored.