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

Question

Ignoring the special libraries that allow you to work with very big numbers, what's the largest int value you can store in PHP?

Answer 1

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).

Answer 2

(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.

Answer 3

32-bit builds of PHP:

• Integers can be from -2,147,483,648 to 2,147,483,647 (~ ± 2 billion)

64-bit builds of PHP:

• Integers can be from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (~ ± 9 quintillion)

Numbers are inclusive.

Note: some 64-bit builds once used 32-bit integers, particularly older Windows builds of PHP

Values outside of these ranges are represented by floating point values, as are non-integer values within these ranges. The interpreter will automatically determine when this switch to floating point needs to happen based on whether the result value of a calculation can't be represented as an integer.

PHP has no support for "unsigned" integers as such, limiting the maximum value of all integers to the range of a "signed" integer.

Answer 4

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)

Answer 5

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.

Answer 6

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