Random number in range [min - max] using PHP

Question

Is there a way to generate a random number based on a min and max?

For example, if min was 1 and max 20 it should generate any number between 1 and 20, including 1 and 20?

Answer 1

<?php
  $min=1;
  $max=20;
  echo rand($min,$max);
?>

Answer 2

In a new PHP7 there is a finally a support for a cryptographically secure pseudo-random integers.

int random_int ( int $min , int $max )

random_int — Generates cryptographically secure pseudo-random integers

which basically makes previous answers obsolete.

Answer 3

A quicker faster version would use mt_rand:

$min=1;
$max=20;
echo mt_rand($min,$max);

Source: http://www.php.net/manual/en/function.mt-rand.php.

NOTE: Your server needs to have the Math PHP module enabled for this to work. If it doesn't, bug your host to enable it, or you have to use the normal (and slower) rand().

Answer 4

I have bundled the answers here and made it version independent;

function generateRandom($min = 1, $max = 20) {
    // Prioritize `random_int` for security
    if (function_exists('random_int')) {
        return random_int($min, $max); // more secure
    }

    // Fallback to `mt_rand` if `random_int` isn't available
    if (function_exists('mt_rand')) {
        return mt_rand($min, $max); // faster
    }

    // Use `rand` as a last resort.
    // Uncomment line below to warn about potential issues
    // trigger_error("Using less secure 'rand' function for random number generation. Consider upgrading your PHP version.", E_USER_WARNING);
    return rand($min, $max); // old
}

Answer 5

(rand() % ($max-$min)) + $min

or

rand ( $min , $max )

http://php.net/manual/en/function.rand.php

Answer 6

rand(1,20)

Docs for PHP's rand function are here:

http://php.net/manual/en/function.rand.php

Use the srand() function to set the random number generator's seed value.

Answer 7

Try This one. It will generate id according to your wish.

function id()
{
 // add limit
$id_length = 20;

// add any character / digit
$alfa = "abcdefghijklmnopqrstuvwxyz1234567890";
$token = "";
for($i = 1; $i < $id_length; $i ++) {

  // generate randomly within given character/digits
  @$token .= $alfa[rand(1, strlen($alfa))];

}    
return $token;
}