Data Length for Rich Text fields

I have noticed that the data length for a rich text field seems to be padded a bit.

Example:

I have text document that contains 4,523 bytes of HTML code. When this code is copied into a Rich Text field in a Notes document and saved the data length comes out to be 6,422 bytes.

Is this overhead generated by Rich Text properties in the field?

TIA

Subject: Data Length for Rich Text fields

Part of it is CD record overhead, but part of it is also that Notes uses multibyte characters (unlike a straight-up text file).