IMO number checker

Client

Fleet spreadsheets and compliance tickets often paste IMO ship identification numbers beside MMSI or flag-state codes. This page strips an optional IMO prefix, confirms seven decimal digits, and recomputes the published weighted check—pair with VIN checksum when the same row lists road vehicles.

What this checks

An IMO ship identification number is seven decimal digits: six body digits plus a weighted mod‑10 check. Weights on the body are 7, 6, 5, 4, 3, 2—the tool confirms layout and recomputes the seventh digit; it does not prove registry or flag.

Privacy: checksum math runs locally in your tab. Toolcore does not query the IMO ship registry or maritime databases—format and check digit only.
?

After cleanup the value is 7 decimal digits (optional leading IMO). Multiply the first six digits by weights 7, 6, 5, 4, 3, 2 and take the sum mod 10 for the seventh digit.

Result

Passes IMO weighted check for IMO9074729.

Body (6)
907472
Check digit
9

Nearby workflows on Toolcore

  • VIN checksum — when the same onboarding pack mixes maritime and road-vehicle identifiers.
  • ICCID check — for SIM and cellular identifiers beside fleet spreadsheets.
  • GTIN check — when supply-chain GTINs appear in the same file as vessel rows.

Common use cases

  • Sanity-check an IMO copied from a charter party or fleet CSV before loading it into an internal vessel master.
  • Explain why a seven-digit IMO fails checksum while a related MMSI field still looks numeric.
  • Spot transposed digits in the six-digit body during maritime onboarding when only the IMO column is available.
  • Contrast IMO weights (7, 6, 5, 4, 3, 2) with securities identifiers that use different mod‑10 chains.

Common mistakes to avoid

  • Treating a passing check as proof of registry or flag

    Checksum validation confirms arithmetic only—not ownership, class society status, or AIS authenticity.

  • Applying ISIN or CUSIP doubling to IMO bodies

    IMO multiplies the first six decimal digits by 7, 6, 5, 4, 3, 2 respectively, then takes sum mod 10 for the seventh digit.

  • Expecting IMO ship registry metadata

    Vessel name, flag, and tonnage require official or licensed feeds—this page performs local format math only.

FAQ

Does Toolcore query the IMO ship registry?

No—the check digit and layout rules run entirely in your browser tab.

How does the check digit work?

Multiply the first six digits by weights 7, 6, 5, 4, 3, 2, sum the products, and take the result mod 10 as the seventh digit.

Can I paste the IMO prefix?

Yes—spaces and an optional IMO prefix are stripped; only seven decimal digits remain after cleanup.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • imo number checker online check digit
  • validate imo ship identification number
  • imo checksum weighted mod 10 browser
  • vessel imo validate no registry lookup

More tools

Related utilities you can open in another tab—mostly client-side.