php man page for round

ROUND(3)								 1								  ROUND(3)

round - Rounds a float

SYNOPSIS
       float round (float  $val, [int  $precision], [int  $mode = PHP_ROUND_HALF_UP])

DESCRIPTION
	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.

PARAMETERS
	      o $val
		- The value to round

	      o $precision
		- The optional number of decimal digits to round to.

	      o $mode
		- Use 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.			       |
	      | 		   |						       |
	      +--------------------+---------------------------------------------------+
RETURN VALUES
	The rounded value

EXAMPLES
       Example #1

	      round(3) 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
	      ?>

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.3.0	|						    |
       |	|						    |
       |	|	 The $mode parameter was introduced.	    |
       |	|						    |
       | 5.2.7	|						    |
       |	|						    |
       |	|  The inner workings of round(3)  was	changed  to |
       |	| conform to the C99 standard.			    |
       |	|						    |
       +--------+---------------------------------------------------+
SEE ALSO
       ceil(3), floor(3), number_format(3).

PHP Documentation Group 														  ROUND(3)