Home Asmens kodas Lithuania
Lithuania Asmens kodas validator
How the Asmens kodas format works
- Format
- 11 digits
- Example
- 33309240064
Things to watch for
- 11 digits validated with the same two-pass weighted mod-11 check used by Estonia's isikukood — a second weight set applies when the first pass produces an undefined remainder
- The first digit encodes sex and century and the next 6 a date of birth — we validate format and checksum only, never the date, and never store what you enter
- Checksum only — a valid asmens kodas does not confirm the number is currently issued to a real person
^[0-9]{11}$An asmens kodas is Lithuania’s 11-digit personal identification code, assigned to residents and recorded in the Gyventojų registras — the country’s Residents’ Register, maintained by the State Enterprise Centre of Registers — for use across tax filings with the State Tax Inspectorate, health insurance, banking, and most government-facing paperwork. Like several of its Baltic neighbors, the code isn’t an arbitrary serial: the first digit marks sex and century, the next six encode a date of birth, three more form a daily serial, and the eleventh is a check digit.
What’s worth calling out explicitly is that this checksum formula isn’t unique to Lithuania — it’s the same two-pass weighted mod-11 calculation Estonia uses for its isikukood. A first weighted sum runs over the first ten digits; only when that sum’s remainder is undefined does a second weighted sum kick in as a fallback. The shared math reflects a shared numbering convention across the two countries’ population registers, even though each register is administered, issued, and kept entirely independently.
How this validator works
This tool checks that the input is 11 digits, then reruns the two-pass weighted mod-11 calculation to confirm the eleventh digit matches — entirely in your browser, with nothing transmitted or stored, even though the code encodes a date of birth and sex.
What a pass doesn’t tell you
A matching checksum confirms the 11 digits are mathematically consistent with each other — not that the asmens kodas was ever issued by Lithuania’s Residents’ Register or is currently assigned to a real person. Only that register can confirm a specific code is genuinely on file.
Scope: this page covers asmens kodas format and checksum validation only — not identity or registration lookups, and never the embedded date of birth or sex.
Content last reviewed 2026-08-09.
Asmens kodas FAQ
What do the 11 digits of a Lithuanian asmens kodas encode?
The first digit encodes sex and century, the next six digits are a date of birth, the following three digits are a serial number, and the eleventh digit is a check digit computed from the other ten — the same layout Estonia uses for its isikukood.
Is the asmens kodas checksum really identical to Estonia's isikukood?
Yes, mathematically. Both use the same two-pass weighted mod-11 formula: a first weighted sum over ten digits, and a fallback second weighted sum only when the first produces an undefined remainder. The two countries share the calculation, but Lithuania's numbers are issued and recorded independently through its own Residents' Register.
Does a valid asmens kodas confirm someone is on file with Lithuania's Residents' Register?
No. It confirms the 11 digits are internally consistent, nothing more. Only the Gyventojų registras (Residents' Register) itself can confirm a specific asmens kodas was genuinely issued.