PHP Math Functions: abs(), sqrt(), pow(), pi() and More

PHP comes with a set of built-in math functions. You do not need a library for everyday calculations.

Function	What it does	Example
`abs($n)`	Absolute value (removes the minus)	`abs(-5)` gives `5`
`sqrt($n)`	Square root	`sqrt(16)` gives `4`
`pow($a, $b)`	Power, same as `**`	`pow(2, 3)` gives `8`
`intdiv($a, $b)`	Whole-number division	`intdiv(7, 2)` gives `3`
`fmod($a, $b)`	Remainder for floats	`fmod(7.5, 2)` gives `1.5`
`pi()` or `M_PI`	The number pi	`3.14159...`
`floor($n)`	Round down	`floor(4.9)` gives `4`
`ceil($n)`	Round up	`ceil(4.1)` gives `5`

index.php

PHP

<?php
echo abs(-12) . "\n";
echo sqrt(81) . "\n";
echo pow(2, 10) . "\n";
echo intdiv(17, 5) . "\n";
echo fmod(10.5, 3) . "\n";
echo M_PI;

Output

OUTPUT

12
9
1024
3
1.5
3.1415926535898

An area calculator

index.php

PHP

<?php
function circleArea(float $radius): float
{
    return M_PI * $radius ** 2;
}

echo round(circleArea(5), 2);

Output

OUTPUT

78.54

index.php

PHP

<?php
echo 2 ** 8 . "\n";       // 256
echo 27 ** (1 / 3) . "\n"; // cube root: 3
echo sqrt(2);

Output

OUTPUT

1
2
3

256
3
1.4142135623731

PHP also has log(), log10(), exp(), sin(), cos(), tan() and their relatives. Angles are in radians, not degrees.

index.php

PHP

<?php
echo round(sin(deg2rad(30)), 2) . "\n";
echo log10(1000) . "\n";
echo round(exp(1), 4);

Output

OUTPUT

1
2
3

0.5
3
2.7183

Some maths operations have no valid answer. sqrt(-1) returns NAN (not a number).

index.php

PHP

<?php
$result = sqrt(-1);

var_dump(is_nan($result));

Output

OUTPUT

bool(true)

lightbulb

M_PI, M_E and PHP_INT_MAX are ready to use. Do not type 3.14 by hand when M_PI is more accurate.