VIN check digit

Client

Modern road-vehicle VINs (1981+ model years in the US system) use a fixed-weight sum mod 11 at the ninth character. Compare with digit-only tools like Luhn (mod 10) or IMEI check when you are validating other identifier families.

Privacy: parsing runs only in your browser. This page does not query DMV, insurance, or manufacturer databases—only the published mod-11 rule for the ninth character.
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After removing spaces and hyphens, the frame must be exactly 17 characters. Letters I, O, and Q are forbidden everywhere. Position 9 (index 8) is the check symbol: decimal 0–9 or X for remainder ten. Each symbol maps to a numeric value, is multiplied by a fixed weight for its position, products are summed, and sum mod 11 must equal the check symbol’s value (X → 10).

Result

Passes check digit — weighted sum mod 11 is 10; expected X.

  • WMI (positions 1–3): 1HG
  • Attributes (4–8): BH41J
  • Check (9): X
  • Model year code (10): M
  • Plant (11): N
  • Sequential (12–17): 109186

Common use cases

  • Double-check OCR from a windshield or door-jamb sticker before filing internal fleet spreadsheets.
  • Teach trainees why flipping one ninth-position typo fails mod 11 even when letters look plausible.
  • Pair with IMEI validators when auditing mixed logistics forms that contain both handset and chassis identifiers.
  • Roughly localize WMI / sequential fields when reading engineering samples—remember manufacturers publish deeper decode tables separately.

Common mistakes to avoid

  • Assuming checksum pass proves title or theft clearance

    Only the algebraic relationship between characters is verified here—legal status stays with registries.

  • Using non-US VIN rules on import paperwork

    Other regions may emboss different lengths pre-1981 or use supplemental plates; mismatch is expected.

  • Typing I, O, or Q from handwritten notes

    Those letters are forbidden in standardized VINs specifically to avoid confusing them with digits.

FAQ

Is my VIN sent to Toolcore servers?

No—all transliteration arithmetic happens locally in your tab.

Why can the check symbol be X?

When the remainder modulo eleven is ten, printers use letter X exactly at position nine instead of inventing another digit.

Do you decode model year meanings?

We show position 10 as the raw manufacturer year code—you still need OEM tables for ambiguity (e.g. repeating letters across decades).

Common search terms

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

  • vin check digit verifier online
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  • ninth position vin checksum browser
  • iso 3779 vin check digit calculator
  • vehicle identification number check digit locally

More tools

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