PHP round() Function

The PHP round() function returns the rounded value of the number to specified precision. In special cases it returns the following:

If the argument is NAN, the result is NAN.
If the argument is infinity, the result is equal to the argument.

Syntax

round(number, precision, mode)

Parameters

`number`	`Required.` Specify a floating point value to be rounded.
`precision`	`Optional.` Specify the number of decimal digits to round to. Default is 0.
`mode`	`Optional.` Specify one of the following constants to specify the mode in which rounding occurs: PHP_ROUND_HALF_UP: Default. Rounds number away from zero when it is half way. PHP_ROUND_HALF_DOWN: Rounds number towards zero when it is half way. PHP_ROUND_HALF_EVEN: Rounds number towards the nearest even value when it is half way. PHP_ROUND_HALF_ODD: Rounds number towards the nearest odd value when it is half way.

Return Value

Returns the rounded value of the number to specified precision.

Example:

In the example below, round() function returns the value of argument rounded to zero decimal digits.

<?php
echo "round(10.3) = ".round(10.3)."\n";
echo "round(10.5) = ".round(10.5)."\n";
echo "round(10.7) = ".round(10.7)."\n";
echo "round(-9.3) = ".round(-9.3)."\n";
echo "round(-9.5) = ".round(-9.5)."\n";
echo "round(-9.7) = ".round(-9.7)."\n";
echo "round(INF) = ".round(INF)."\n";
echo "round(-INF) = ".round(-INF)."\n";
echo "round(NAN) = ".round(NAN)."\n";
?>

The output of the above code will be:

round(10.3) = 10
round(10.5) = 11
round(10.7) = 11
round(-9.3) = -9
round(-9.5) = -10
round(-9.7) = -10
round(INF) = INF
round(-INF) = -INF
round(NAN) = NAN

Example:

The example below illustrates on optional parameters of round() function.

<?php
//using precision parameter
echo "M_PI = ".M_PI."\n";
echo "round(M_PI, 2) = ".round(M_PI, 2)."\n";
echo "round(M_PI, 3) = ".round(M_PI, 3)."\n";

//using modes with precision parameter
echo "\nround(10.5, 0, PHP_ROUND_HALF_UP) = "
     .round(10.5, 0, PHP_ROUND_HALF_UP)."\n";
echo "round(10.5, 0, PHP_ROUND_HALF_DOWN) = "
     .round(10.5, 0, PHP_ROUND_HALF_DOWN)."\n";
echo "round(10.5, 0, PHP_ROUND_HALF_EVEN) = "
     .round(10.5, 0, PHP_ROUND_HALF_EVEN)."\n";
echo "round(10.5, 0, PHP_ROUND_HALF_ODD) = "
     .round(10.5, 0, PHP_ROUND_HALF_ODD)."\n";
?>

The output of the above code will be:

M_PI = 3.1415926535898
round(M_PI, 2) = 3.14
round(M_PI, 3) = 3.142

round(10.5, 0, PHP_ROUND_HALF_UP) = 11
round(10.5, 0, PHP_ROUND_HALF_DOWN) = 10
round(10.5, 0, PHP_ROUND_HALF_EVEN) = 10
round(10.5, 0, PHP_ROUND_HALF_ODD) = 11

❮ PHP Math Reference