round()

round() — Rounds a float.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

Returns the rounded value of num to specified precision (number of digits after the decimal point). precision can also be negative or zero (default).

Signature

round(int|float $num, int $precision = 0, int|RoundingMode $mode = RoundingMode::HalfAwayFromZero): float

Parameters

Parameter	Type	What it takes
$num	int\|float	The value to round.
$precision	int	The optional number of decimal digits to round to.
$mode	int\|RoundingMode	Use RoundingMode or one of the following constants to specify the mode in which rounding occurs. Constants Description PHP_ROUND_HALF_UP Rounds num away from zero when it is half way there, making 1.5 into 2 and -1.5 into -2. PHP_ROUND_HALF_DOWN Rounds num towards zero when it is half way there, making 1.5 into 1 and -1.5 into -1. PHP_ROUND_HALF_EVEN Rounds num towards the nearest even value when it is half way ...

Return value

The value rounded to the given precision as a float.

Example

A runnable snippet:

var_dump(round(3.4)); var_dump(round(3.5)); var_dump(round(3.6)); var_dump(round(3.6, 0)); var_dump(round(5.045, 2)); var_dump(round(5.055, 2)); var_dump(round(345, -2)); var_dump(round(345, -3)); var_dump(round(678, -2)); var_dump(round(678, -3));

Output:

float(3) float(4) float(4) float(4) float(5.05) float(5.06) float(300) float(0) float(700) float(1000)

Changelog

Version	Change
8.4.0	Four new rounding modes have been added.
8.4.0	Now throws a ValueError if mode is invalid.
8.0.0	num no longer accepts internal objects which support numeric conversion.