How to calculate file size in php?

It’s so easy … you need to know that the count is in bytes (B).

Now we go to calculate:

1 KB = 1.024 B

1 MB = 1.024 KB = 1.048.576 B

1 GB = 1.024 MB = 1.048.576 KB = 1.073.741.824 B

1 TB = 1.024 GB = 1.048.576 MB = 1.073.741.824 KB = 1.099.511.627.776 B

The most simple form to you calculate in your PHP code is defined constants with type of sizes. Ex:

define('KB', 1024);
define('MB', 1048576);
define('GB', 1073741824);
define('TB', 1099511627776);

Now it’s easy.

Ex 1. If you want a file less to 10MB:

if ($_FILES['file']['size'] < 10*MB)

Ex 2. If you want a file less to 1GB:

if ($_FILES['file']['size'] < GB)