Identify a Hublot From a Photo: Reference and Serial Guide

Turn the watch over. Hublot engraves both numbers on the caseback, usually a screwed-down back with a sapphire window. The reference is a dot-separated code such as 301.SB.131.RX or 542.NX.1171.LR; the serial number is a numeric code of around six digits engraved nearby. Depending on the model they sit on the rim around the sapphire, on the flat of the back or across its flank.

Limited editions add a third engraving, the edition number in the form 123/500. The same reference and serial appear on the warranty card, digital for recent watches. If a seller cannot show you the caseback, ask for a photograph of it first.

Hublot does not engrave the reference between the lugs as Rolex does, and the dial carries no reference, only HUBLOT and GENEVE and sometimes the collection name. Watches from before the 2005 relaunch often read MDM Genève, the name of the original company, and follow an older numbering not covered here. For the cross-brand view, see watch reference numbers explained.

A modern Hublot reference has four groups separated by dots, with an optional fifth for gem-setting. Hublot has never published a key; the meanings below are patterns collectors have reconstructed from the catalogue, and they hold consistently for watches made since 2005.

1. Model family and size (three digits): 301 is the original Big Bang 44 mm chronograph, 441 the Big Bang Unico 42, 511 the Classic Fusion 45.
2. Case material (two letters): SX steel, NX titanium, OX King Gold, CI or CM black ceramic. The first letter is the reliable part; the second changes when the bezel differs from the case.
3. Dial, bezel and finish (three or four digits): 130 and 131 on the first Big Bang, 1170 on black openworked Unico dials, 1171 on black Classic Fusion dials, 7170 on blue dials.
4. Strap or bracelet (two letters): RX black rubber, LR rubber-lined leather, or a repeat of the case code for a matching bracelet.

Common letter codes in the second group: SX steel, SB steel with a black ceramic bezel, PX and PB 18k red gold on early Big Bangs, NX titanium, NM titanium with a ceramic bezel, OX King Gold (Hublot's red gold alloy), OM King Gold with a ceramic bezel, CI and CM black ceramic, QX carbon fibre, JX sapphire; MX commonly denotes Magic Gold. In the fourth group, RX is black rubber, LR rubber-lined leather and RT the transparent rubber of the sapphire models. A fifth group of digits, for example .1104, indicates a diamond-set bezel or case.

The serial is unique to the watch and is the number Hublot, insurers and dealers record. It is not a date code. Hublot does not publish a serial-to-year table, and there is no collector chart as there is for Rolex, so a serial on its own cannot be turned into a production year. The reliable sources are the warranty card date and Hublot's own records, which a boutique or service centre can check.

What you can do is date by reference generation, since each family has a known launch window. The ranges are approximate: they describe when a design was introduced, not when a given watch was made, and many references stayed in production for a decade or more.

• 1980 to the early 2000s: the original Hublot, gold or steel porthole cases with a screwed bezel (twelve screws on the first model) and a rubber strap, made under the MDM Genève name.
• 2005 onward: Big Bang 44 mm (301 series), followed by other sizes and the All Black in 2006; closed dials and a Valjoux 7750-derived chronograph calibre.
• Around 2010: Classic Fusion (511, 542 and related series) and the in-house Unico chronograph calibre, first seen in the oversized King Power before the Big Bang Unico 45 mm (411 series) arrived in 2013.
• 2014: Spirit of Big Bang (601 series), the barrel-shaped case.
• Late 2010s: Big Bang MECA-10 (714 series) and Unico Sapphire in 2016, Big Bang Unico 42 mm (441 series) with One Click straps in 2018.
• 2020 onward: Big Bang Unico 44 mm (421 series) replacing the 45, Big Bang Integral (451 series) on a bracelet, Square Bang Unico (821 series) in 2022.

Combine the generation with physical cues: One Click lugs place a Big Bang in the late 2010s or later, an openworked dial with a visible column wheel means a Unico calibre and therefore 2013 or later, and MDM on the dial means pre-relaunch. Treat any year arrived at this way as an estimate.

Almost every Hublot shares the porthole bezel and its six H-shaped screws, so the bezel alone does not identify a collection. Case shape, thickness and dial do.

• Big Bang: a thick, layered case with black composite inserts between bezel and case middle, bezel lugs and a rubber-clad crown and pushers. The first generation (301 and 341 series) is a chronograph with two counters and a date at 4:30 on a closed dial. The Art of Fusion mixes live here: steel or gold with ceramic, titanium with carbon, King Gold, Magic Gold, coloured ceramics and sapphire.
• Big Bang Unico: the same case architecture with an openworked dial, the chronograph column wheel visible at 6 o'clock, a 60-minute counter at 3 with the date set into it, running seconds at 9, and on the 42 and 44 mm versions the One Click strap pushers in the lugs.
• Big Bang Integral: the Unico case on an integrated bracelet in the case material, with no strap at all.
• Big Bang MECA-10: a manual-wind skeleton with a rack-driven ten-day power-reserve display across the dial and no chronograph pushers.
• Classic Fusion: noticeably thinner and flatter, with a smooth bezel, slimmer lugs and a plain sunray dial with applied indices and a date at 6 o'clock. The chronograph version adds two counters at 3 and 9; the Aerofusion versions open up the dial.
• Spirit of Big Bang: a tonneau (barrel-shaped) case with the Big Bang's layered construction, usually with an openworked chronograph dial.
• Square Bang: a square case with rounded corners, introduced in 2022, carrying the Unico movement and dial layout.
• MP collection: Masterpiece pieces such as the MP-05 LaFerrari and MP-11, with multi-barrel movements, long power reserves and case shapes that owe nothing to the porthole, made in small series.

• Big Bang or Big Bang Unico: a closed dial with two counters and a date at 4:30 is a first-generation Big Bang; an openworked dial with the column wheel visible at 6 and the date at 3 is a Unico. The references differ too: 301 and 341 against 411, 421 and 441.
• Big Bang Unico or Big Bang Integral: the Integral is on a bracelet in the case material and its reference ends in that code (451.NX.1170.NX) instead of RX or LR.
• Classic Fusion or Big Bang: a Classic Fusion is slim, with a smooth bezel and no exposed composite inserts; a Big Bang is thick and layered, with inserts, bezel lugs and chunky pushers. Three-hand Classic Fusions have the date at 6; Big Bang chronographs at 3 or 4:30.
• Spirit of Big Bang or Big Bang: the Spirit is barrel-shaped; every Big Bang is round.
• Hublot or Audemars Piguet Royal Oak Offshore: both are chunky sports chronographs with exposed bezel screws, but the Offshore's bezel is octagonal with eight hexagonal screws and Hublot's is round with six H-shaped screws. See our Audemars Piguet guide.
• Replicas and look-alikes: the Big Bang is among the most copied watch designs anywhere, and many fashion brands sell porthole-and-screws watches of their own. Collectors check the finish and alignment of the H-screws, the marking of the rubber strap and the crispness of the caseback engraving. A photo match says nothing about which of these a watch is; read our guide to spotting a fake luxury watch for the method.
• Limited editions: Hublot issues many partner editions, from football and motorsport to music and art, with their own reference blocks, an edition number on the caseback and often a partner logo. Expect WatchID to propose the underlying model when the edition itself is not in the database.

Hublot suits photo identification well: the collections are visually distinct, and the caseback reference gives you a hard check on whatever the picture suggests. Upload a photo to WatchID and it compares case shape, bezel, dial layout, materials and strap against known Hublot references and returns ranked candidates; a titanium chronograph with an openworked dial comes back as a Big Bang Unico with 441.NX.1170.RX and 421.NX.1170.RX to tell apart by size.

1. Photograph the dial straight on, without flash, so the counters, date position and text are legible.
2. Photograph the caseback; the dotted reference confirms or rules out the candidates.
3. Add a side view if you can; thickness and strap attachment separate a Classic Fusion from a Big Bang.
4. Compare the suggested reference with the engraving segment by segment: a 511 is a 45 mm watch, not a 42, and an LR code on a watch wearing rubber suggests a changed strap.

Limits: a photo cannot reliably distinguish titanium from steel, cannot read a serial, and cannot confirm the movement or the originality of a strap. For the general method read how to identify a watch from a photo and how to identify a watch. To see identified references on the market, browse the Hublot listings on Horoview; if you are weighing a Hublot against another LVMH sports chronograph, our TAG Heuer guide covers the Carrera and Monaco.