(PHP 4, PHP 5, PHP 7)
round — Rounds a float
$val
[, int $precision = 0
[, int $mode = PHP_ROUND_HALF_UP
]] )
Returns the rounded value of val to
specified precision
(number of digits after the decimal point).
precision can also be negative or zero (default).
Note: PHP doesn't handle strings like "12,300.2" correctly by default. See converting from strings.
valThe value to round
precisionThe optional number of decimal digits to round to.
modeUse one of the following constants to specify the mode in which rounding occurs.
| Constant | Description |
|---|---|
PHP_ROUND_HALF_UP |
Round val up to precision decimal places
away from zero, when it is half way there. Making 1.5 into 2 and -1.5 into -2.
|
PHP_ROUND_HALF_DOWN |
Round val down to precision decimal places
towards zero, when it is half way there. Making 1.5 into 1 and -1.5 into -1.
|
PHP_ROUND_HALF_EVEN |
Round val to precision decimal places
towards the next even value.
|
PHP_ROUND_HALF_ODD |
Round val to precision decimal places
towards the next odd value.
|
The rounded value
Example #1 round() examples
<?php
echo round(3.4); // 3
echo round(3.5); // 4
echo round(3.6); // 4
echo round(3.6, 0); // 4
echo round(1.95583, 2); // 1.96
echo round(1241757, -3); // 1242000
echo round(5.045, 2); // 5.05
echo round(5.055, 2); // 5.06
?>
Example #2 mode examples
<?php
echo round(9.5, 0, PHP_ROUND_HALF_UP); // 10
echo round(9.5, 0, PHP_ROUND_HALF_DOWN); // 9
echo round(9.5, 0, PHP_ROUND_HALF_EVEN); // 10
echo round(9.5, 0, PHP_ROUND_HALF_ODD); // 9
echo round(8.5, 0, PHP_ROUND_HALF_UP); // 9
echo round(8.5, 0, PHP_ROUND_HALF_DOWN); // 8
echo round(8.5, 0, PHP_ROUND_HALF_EVEN); // 8
echo round(8.5, 0, PHP_ROUND_HALF_ODD); // 9
?>
Example #3 mode with precision examples
<?php
/* Using PHP_ROUND_HALF_UP with 1 decimal digit precision */
echo round( 1.55, 1, PHP_ROUND_HALF_UP); // 1.6
echo round( 1.54, 1, PHP_ROUND_HALF_UP); // 1.5
echo round(-1.55, 1, PHP_ROUND_HALF_UP); // -1.6
echo round(-1.54, 1, PHP_ROUND_HALF_UP); // -1.5
/* Using PHP_ROUND_HALF_DOWN with 1 decimal digit precision */
echo round( 1.55, 1, PHP_ROUND_HALF_DOWN); // 1.5
echo round( 1.54, 1, PHP_ROUND_HALF_DOWN); // 1.5
echo round(-1.55, 1, PHP_ROUND_HALF_DOWN); // -1.5
echo round(-1.54, 1, PHP_ROUND_HALF_DOWN); // -1.5
/* Using PHP_ROUND_HALF_EVEN with 1 decimal digit precision */
echo round( 1.55, 1, PHP_ROUND_HALF_EVEN); // 1.6
echo round( 1.54, 1, PHP_ROUND_HALF_EVEN); // 1.5
echo round(-1.55, 1, PHP_ROUND_HALF_EVEN); // -1.6
echo round(-1.54, 1, PHP_ROUND_HALF_EVEN); // -1.5
/* Using PHP_ROUND_HALF_ODD with 1 decimal digit precision */
echo round( 1.55, 1, PHP_ROUND_HALF_ODD); // 1.5
echo round( 1.54, 1, PHP_ROUND_HALF_ODD); // 1.5
echo round(-1.55, 1, PHP_ROUND_HALF_ODD); // -1.5
echo round(-1.54, 1, PHP_ROUND_HALF_ODD); // -1.5
?>
| Version | Description |
|---|---|
| 5.3.0 |
The mode parameter was introduced.
|
| 5.2.7 | The inner workings of round() was changed to conform to the C99 standard. |