A Latvian IBAN is always 21 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.
Latvia identifies the bank with four letters and gives the remaining thirteen characters to the account, which may contain letters as well as digits. Like Lithuania, Latvia hosts payment institutions whose IBANs are used far beyond the country itself.
The two digits straight after LV 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 21 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 21, always. That is LV, two check digits, and 17 characters of account detail. Anything longer or shorter is not a valid LV IBAN, whatever else is right about it.
It is the 4 characters directly after the check digits. In the example LV80 BANK 0000 4351 9500 1, that is BANK.
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.