Validate IMO numbers using the official checksum (or generate valid ones) with batch mode.
Your vote is saved on this device only.
An IMO number is a seven-digit ship identifier whose final digit is a checksum derived from the first six. This tool checks any IMO number against that official check-digit formula, instantly telling you whether it is valid or where it fails. You can also generate correctly formed IMO numbers for testing, and run a whole list at once in batch mode instead of verifying entries one by one.
It is built for maritime data teams, developers, brokers, port and registry staff, and anyone cleaning vessel records who needs to catch typos before they propagate. The tool is free and runs entirely in your browser, so the vessel numbers you paste in are validated locally and never sent to any server.
The first six digits are each multiplied by a descending weight (7 through 2), the products are summed, and the last digit of that sum must equal the seventh digit. This tool applies that exact rule.
No. All validation and generation happen locally in your browser, so nothing you enter is transmitted or stored on a server. It also works offline once the page has loaded.
A single mistyped digit will break the checksum even if the number looks plausible. The tool flags exactly these transcription errors, which is its main purpose.
The validator focuses on the seven-digit number itself. Strip any 'IMO' prefix, spaces, or punctuation so it reads as seven plain digits before checking.
Because processing runs in your browser, you can validate sizeable lists at once, limited only by your device's memory rather than any server quota.