What's the maximum value for an int in PHP?

From the PHP manual:

The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value (that's 32 bits signed). PHP does not support unsigned integers. Integer size can be determined using the constant PHP_INT_SIZE, and maximum value using the constant PHP_INT_MAX since PHP 4.4.0 and PHP 5.0.5.

64-bit platforms usually have a maximum value of about 9E18, except on Windows prior to PHP 7, where it was always 32 bit.

The size of PHP ints is platform dependent:

The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value (that's 32 bits signed). PHP does not support unsigned integers. Integer size can be determined using the constant PHP_INT_SIZE, and maximum value using the constant PHP_INT_MAX since PHP 4.4.0 and PHP 5.0.5.

PHP 6 adds "longs" (64 bit ints).

(a little bit late, but could be useful)

Only trust PHP_INT_MAX and PHP_INT_SIZE, this value vary on your arch (32/64 bits) and your OS...

Any other "guess" or "hint" can be false.

Ah I found it: 2³² - 1 (2147483647)

http://au2.php.net/int

Integer overflow

If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead. Also, an operation which results in a number beyond the bounds of the integer type will return a float instead.

<?php
$large_number =  2147483647;
var_dump($large_number);
// output: int(2147483647)

$large_number =  2147483648;
var_dump($large_number);
// output: float(2147483648)

It depends on your OS, but 2147483647 is the usual value, according to the manual.

It subjects to architecture of the server on which PHP runs. For 64-bit,

print PHP_INT_MIN . ", ” . PHP_INT_MAX; yields -9223372036854775808, 9223372036854775807

Although PHP_INT_* constants exist for a very long time, the same MIN / MAX values could be found programmatically by left shifting until reaching the negative number:

$x = 1;
while ($x > 0 && $x <<= 1);
echo "MIN: ", $x;
echo PHP_EOL;
echo "MAX: ", ~$x;