(PHP 4, PHP 5, PHP 7, PHP 8)
rand — Generate a random integer
If called without the optional min,
max arguments rand()
returns a pseudo-random integer between 0 and
getrandmax(). If you want a random number
between 5 and 15 (inclusive), for example, use rand(5,
15).
This function does not generate cryptographically secure values, and must not be used for cryptographic purposes, or purposes that require returned values to be unguessable.
If cryptographically secure randomness is required, the Random\Randomizer may be used with the Random\Engine\Secure engine. For simple use cases, the random_int() and random_bytes() functions provide a convenient and secure API that is backed by the operating system’s CSPRNG.
Note: On some platforms (such as Windows), getrandmax() is only 32767. If you require a range larger than 32767, specifying
minandmaxwill allow you to create a range larger than this, or consider using mt_rand() instead.
Note: As of PHP 7.1.0, rand() uses the same random number generator as mt_rand(). To preserve backwards compatibility rand() allows
maxto be smaller thanminas opposed to returningfalseas mt_rand().
minThe lowest value to return (default: 0)
maxThe highest value to return (default: getrandmax())
A pseudo random value between min
(or 0) and max (or getrandmax(), inclusive).
| Version | Description |
|---|---|
| 7.2.0 | rand() has received a bug fix for a modulo bias bug. This means that sequences generated with a specific seed may differ from PHP 7.1 on 64-bit machines. |
| 7.1.0 | rand() has been made an alias of mt_rand(). |
Example #1 rand() example
<?php
echo rand(), "\n";
echo rand(), "\n";
echo rand(5, 15), "\n";
?>The above example will output something similar to:
7771 22264 11
min max range must
be within the range getrandmax(). i.e. (max -
min) <= getrandmax()
Otherwise, rand() may return poor-quality random numbers.