Floating-point cheat sheet for PHP
Floating-Point Types
PHP is dynamically typed and will often convert implicitly between strings and floating-point numbers (which are platform-dependant, but typically IEEE 64 bit values). To force a value to floating-point, evaluate it in a numerical context:
$foo = 0 + "10.5";
Decimal Types
The BC Math extension implements arbitrary-precision decimal math:
$a = '0.1';
$b = '0.2';
echo bcadd($a, $b); // prints 0.3
How to Round
Rounding can be done with the number_format() function:
$number = 4.123;
echo number_format($number, 2); // prints 4.12
Resources
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