Chapter 5. Numbers

Another fundamental building block of data in PHP is numbers. It’s easy to find different types of numbers in the world around us. The page number in a book is often printed in the footer. Your smartwatch displays the current time and perhaps the number of steps you’ve taken today. Some numbers can be impossibly large, others impossibly small. Numbers can be whole, fractional, or irrational like π.

In PHP, numbers are represented natively in one of two formats: as integers (the int type) or as floating-point numbers (the float type). Both numeric types are highly flexible, but the range of values you can use depends on the processor architecture of your system—​a 32-bit system has tighter bounds than a 64-bit system.

PHP defines several constants that help programs understand the available range of numbers in the system. Given that the capabilities of PHP will differ greatly based on how it was compiled (for 32 or 64 bits), it is wise to use the constants defined in Table 5-1 rather than trying to determine what these values will be in a program. It’s always safer to defer to the operating system and language defaults.

Table 5-1. Constant numeric values in PHP
Constant Description


The largest integer value supported by PHP. On 32-bit systems, this will be 2147483647. On 64-bit systems, this will be 9223372036854775807.


The smallest integer value supported by PHP. On 32-bit systems, this will be -2147483648. On 64-bit systems, ...

Get PHP Cookbook now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.