Free Tool
Hublot Caseback Checker
Check a Hublot reference number, serial, and limited-edition number against the formats Hublot uses. Hublot publishes no serial-to-year table, so this checks the shape and the internal consistency — it cannot date the watch or confirm it is genuine.
Where to find the numbers
- Reference number: engraved on the caseback, dot-separated — a 3-digit model block, a 2-letter case-material code, then bracelet and dial codes (e.g.
301.SB.131.RX). - Serial number: also on the caseback — a short letter-and-digit code identifying the individual watch.
- Limited-edition number: on limited pieces, engraved as “piece / size”, e.g.
088/500.
Enter the caseback details
Hublot does not publish a serial-to-year table, so this is a format and consistency check, not a date decode. Enter what is engraved on the caseback. The reference is dot-separated (e.g. 301.SB.131.RX); the serial is a short letter-and-digit code; the limited-edition number is “piece / size”.
A correct caseback format is a starting point, not proof.
Hublot keeps its production records private. The six H-shaped bezel screws (all clocked the same way on a genuine watch), the movement, and the engraving depth still have to be checked. Get a professional authentication →
Case-Material Codes
The second block of a Hublot reference is a 2-letter case-material code. This list is cross-referenced from retailer listings and collector references; Hublot adds codes, so an unlisted code is not automatically wrong — but it should match the metal you are looking at.
| Code | Material |
|---|---|
| NX | Titanium |
| SX / SB | Stainless steel (SB: with black elements) |
| CX / CM | Ceramic |
| OX / OM | King Gold (Hublot red-gold alloy) |
| MX | Magic Gold / ceramic composite |
| JX / PX / PM | Platinum |
| BX | Carbon |
| RX | Rubber / composite accent (often a dial-style suffix) |
Limited-edition number doesn't add up?
A genuine limited piece is always “n of N” with n ≤ N, and N matches the published run for that exact edition. Counterfeiters often engrave a round size (500, 1000) that does not match the real edition, or a piece number higher than the run.
Want the full authentication guide?
Read How to spot a fake Hublot for the bezel-screw alignment, the HUB movement checks, the ceramic and King Gold weight tells, and the sapphire-dial finishing — in the order a professional runs them.
Frequently asked questions
- Where is the serial number on a Hublot?
- On the caseback. A modern Hublot caseback carries a dot-separated reference number (a 3-digit model block, a 2-letter case-material code, then bracelet and dial codes, for example 301.SB.131.RX), a short letter-and-digit serial number that identifies the individual watch, and on limited pieces a limited-edition number engraved as piece over size, for example 088/500.
- Can a Hublot serial number be dated?
- No. Hublot does not publish a serial-to-year table and does not confirm serials for the public, so the serial cannot be turned into a production year. This checker validates the format of the reference, serial and limited-edition number, and flags internal contradictions such as a piece number higher than the edition size. It cannot date the watch or confirm it is genuine.
- What is the fastest physical check on a Hublot?
- The six H-shaped screws on the bezel. On a genuine Hublot they are all clocked — aligned — the same way. Screws that point in random directions are a common counterfeit giveaway. After that, check the movement (a modern Hublot sweeps, it does not tick once per second) and the depth and crispness of the caseback engraving.
- My Hublot's limited-edition number looks wrong — what should it be?
- A genuine limited piece is always numbered n of N with n no higher than N, and N has to match the published size of that exact edition. Counterfeiters often engrave a round number like 500 or 1000 that does not correspond to the real run, or a piece number that exceeds the edition size. Cross-check the size against Hublot's published figure for that specific reference.