floor() function returns the closest smaller integer. If the argument is an integer, then return the integer.

<?PHP
	echo floor(3.2);  //3
	echo floor(-3.4);  //-4
	echo floor(3);  //3
	echo floor(-4);  //-4
?>

ceil() function returns the closest larger integer. If the argument is an integer, then return the integer.

<?PHP
	echo ceil(3.2);  //4
	echo ceil(-3.4);  //-3
	echo ceil(3);  //3
	echo ceil(-4);  //-4
?>