Calculate the size of a VARBINARY field required for AES_ENCRYPT

Here’s a simple Open Document Format spreadsheet tool to help you calculate 16 × (trunc(string_length / 16) + 1) without having to be a mathematical genius.

Download: AES_ENCRYPT Size Calculator

You can use an ODS compatible spreadsheet program such as LibreOffice or OpenOffice.

Why you may desire to use VARBINARY() instead of VARCHAR(), see this great post from Mahmud Ahsan: