PHP 7.4.8 Released!

# pow

(PHP 4, PHP 5, PHP 7)

powExponential expression

### Description

pow ( number `\$base` , number `\$exp` ) : number

Returns `base` raised to the power of `exp`.

Note:

In PHP 5.6 onwards, you may prefer to use the ** operator.

`base`

The base to use

`exp`

The exponent

### Return Values

`base` raised to the power of `exp`. If both arguments are non-negative integers and the result can be represented as an integer, the result will be returned with integer type, otherwise it will be returned as a float.

### Examples

Example #1 Some examples of pow()

``` <?phpvar_dump(pow(2, 8)); // int(256)echo pow(-1, 20); // 1echo pow(0, 0); // 1echo pow(10, -1); // 0.1echo pow(-1, 5.5); // PHP >=5.2.2: NANecho pow(-1, 5.5); // PHP <5.2.2: -NAN?> ```

### Notes

Note:

This function will convert all input to a number, even non-scalar values, which could lead to weird results.

• exp() - Calculates the exponent of e
• sqrt() - Square root
• bcpow() - Raise an arbitrary precision number to another
• gmp_pow() - Raise number into power add a note

### User Contributed Notes 5 notes

36
chris at ocportal dot com
8 years ago
``` Many notations use "^" as a power operator, but in PHP (and other C-based languages) that is actually the XOR operator. You need to use this 'pow' function, there is no power operator.i.e. 3^2 means "3 XOR 2" not "3 squared".It is particular confusing as when doing Pythagoras theorem in a 'closet points' algorithm using "^" you get results that look vaguely correct but with an error. ```
jaxx1rr at gmail dot com
9 months ago
``` funny thingnumber_format(pow(2, 1023));gives a long numberbut number_format(pow(2, 1024));gives inf ```
raiika
1 year ago
``` It is official now that you could use <?php2 ** 3; // 8// instead ofpow(2, 3); // 8?> ```
13
gilthansREMOVEME at gmail dot com
13 years ago
``` Note that pow(0, 0) equals to 1 although mathematically this is undefined. ```
scott at arciszewski dot me
6 years ago
``` As of PHP 5.6.0alpha2, there is now an exponentiation operator. If this is kept in the final release, it may be worth noting here.<?php// These two will be equivalent as of PHP 5.6.0\$x = \$y ** 2;\$x = pow(\$y, 2);?> ``` 