An Estonian IBAN is always 20 characters long. Here is what each part of it means, with a real example broken down field by field — and a checker that runs on your machine.
Estonia uses the shortest bank code in Europe — just two digits — and gives the remaining fourteen characters to the account number. That makes an Estonian IBAN look almost like one long number after the country code.
The two digits straight after EE are not part of the account — they are a checksum over everything else. Move the first four characters to the end, turn every letter into a number (A=10 … Z=35), divide the result by 97, and a genuine IBAN always leaves a remainder of exactly 1. That is what the box above is doing, on your machine, with nothing sent anywhere.
If the number is on a scanned PDF you cannot select, retyping 20 characters is where mistakes get made. Snip2Field sits on your Windows desktop: press a hotkey, drag a box over the IBAN, and it reads the field, runs this exact checksum and copies it — ready to paste into your books or a transfer form. Fully offline.
See Snip2FieldExactly 20, always. That is EE, two check digits, and 16 characters of account detail. Anything longer or shorter is not a valid EE IBAN, whatever else is right about it.
It is the 2 characters directly after the check digits. In the example EE38 2200 2210 2014 5685, that is 22.
You can tell whether it was written down correctly: the check digits catch a single wrong character or two swapped ones. You cannot tell whether the account exists — only the receiving bank knows that, which is what the recipient-name check does when a transfer is made.