How to Find Your Watch's Model Number: Citizen, Bulova, Invicta, Timex, Casio and More

Where is the model number on a watch?

The short answer, going by the support pages of five brands we track at Bravery Watch: Timex, Casio and Fossil put the number on the back of the watch, Citizen prints it on the hang tag, and Bulova asks to see it, on your warranty card or receipt, when a watch goes in for warranty repair. With no box and no paperwork, start with the caseback; if a friend sent me a photo of a watch and asked what it was, I would first ask for a photo of the back.

Brand	Where the brand says to look	What you find there
Timex	Caseback	Style number, a model code starting with M, a date code
Casio	Back cover	Model number, beside a module number in a small box
Fossil	Back of the watch	Style number, like ES1234
Citizen	Hang tag; box sleeve on online orders	Model number; the caseback has the caliber number
Bulova	Warranty card or proof of purchase	Model number, asked for with warranty repairs
Apple Watch	Apple Watch app on your iPhone: My Watch, General, About	Part number starting with M; tap it for the model number starting with A
Samsung Galaxy Watch	Settings, About watch; underside of the watch	Model number

On Amazon, the Apple Watch listings we track show Apple's part number, such as MJKR4LW/A, not the model number that starts with A.

What does a watch model number look like?

A caseback can carry several numbers, and your brand's format tells you which one is the model number. Brands also call it by different names: Citizen, Bulova and Casio say model number, Timex and Fossil say style number, and Hamilton says reference number. We sorted the 2,740 Amazon model numbers in our catalog by brand, and most brands stick to one format.

Brand	Format	Example	Model numbers in this format
Citizen	2 letters, 4 digits, dash, 2 digits, 1 letter	AT2141-52L	167 of 168
Bulova	2 digits, 1 letter, 3 digits	96B251	71 of 76
Invicta	5 digits	30021	270 of 332
Timex	Starts with TW	TW4B15500	168 of 200
Casio	Letters and digits split by dashes	F-91W-3DG	142 of 166
Guess	2 letters, 4 digits, 1 letter, 1 digit	GW0203G5	174 of 218
Anne Klein	AK/, 4 digits, 4 letters	AK/3774BKGB	88 of 136
Orient	Starts with RA-	RA-AA0001B19B	86 of 105
Hamilton	H and 8 digits	H70455133	74 of 74
Rado	R and 8 digits	R32505313	100 of 102
Longines	L and 8 digits	L37424966	29 of 31
Tissot	T and 13 digits	T1504171104100	5 of 6
Junghans	2 or 3 digits, slash, 4 digits, dot, 2 digits	41/4562.02	51 of 71
Fossil	2 letters, 4 digits	FS5151	17 of 18
Coach	8 digits	14504211	47 of 48
Daniel Wellington	DW and 8 digits	DW00100020	25 of 25
Michael Kors	MK and 4 digits	MK4842	11 of 11
Apple Watch	Part number: starts with M, ends in /A	MJKR4LW/A	15 of 15
Samsung Galaxy Watch	Starts with SM-	SM-L500NZKQXAA	16 of 18
Garmin	Starts with 010-	010-02862-11	24 of 28

These are patterns in our listings, not lists published by the brands; some exceptions are just extra characters added in the listing. Most Orient numbers start with RA-, as on the Orient Kamasu, RA-AA0001B19B. Seiko works differently, with a reference number for the model and a caliber number for the movement; our guide to reading a Seiko reference number explains both.

How do I find the model number on a Citizen watch?

Citizen's support pages say the model number is on the hang tag and, for online orders, under the box sleeve. The caseback carries the caliber number instead, a four-character movement code such as E870, and that still helps if the tag is gone, because Citizen looks up setting instructions by caliber number.

Citizen model numbers are remarkably regular: 167 of the 168 in our catalog use two letters, four digits, a dash, two digits and a letter. So a caseback code with another shape, such as GN-4-S, is probably not the model number.

The digit after the dash gives away the band: when it is 5 to 9, all 93 watches come on a metal bracelet, and when it is 0 to 4, 71 of the 74 whose listing names the band come on a non-metal strap, most often leather. The last letter usually names the dial: all 40 numbers ending in E whose listing gives a dial color have a black dial, and 39 of the 40 ending in L a blue one. This comes from our listings, not from Citizen.

The Citizen Classic Corso, AT2141-52L, is a 42 mm Eco-Drive chronograph with a blue dial on a steel bracelet, just as its number says. The Citizen Promaster Nighthawk, BJ7000-52E, is a 42 mm Eco-Drive with a black dial on a steel bracelet. Our favorite Eco-Drives are in our Citizen Eco-Drive guide.

What Bulova watch do I have?

Most Bulova model numbers in our catalog have six characters, two digits, a letter and three digits: 71 of the 76. The Bulova Lunar Pilot, 96B251, is a 45 mm quartz chronograph on a nylon strap with a black dial. A few Amazon listings add "_FBA" at the end; leave that out when you search.

Bulova's repair page asks for the warranty card or proof of purchase, showing the model number, when a watch goes in under warranty, so if you kept either, look there first. The page does not say where on the watch the number is printed; without the paperwork, start with the caseback and look for that six-character pattern. Bulova's website lists each watch under that number too, and our favorites are in our Bulova guide.

How do I look up an Invicta model number?

Invicta uses plain numbers: most Invictas in our catalog have five digits, a few have four, and a handful add OB to four digits. The Invicta Pro Diver 30021 is a 43 mm Japanese quartz watch with a blue dial on a steel bracelet. The Invicta Pro Diver 8928OB is a 40 mm automatic whose number is one of those ending in OB.

Some listings put INVICTA-, IN- or I- before the digits; if the full code finds nothing, try the digits alone, which is how Invicta's own website lists its watches. Invicta asks for a copy of the warranty card for warranty service, but the pages we checked do not say where on the watch the number is printed; start with the caseback and look for four or five digits. How the Pro Diver models differ is in our Pro Diver buying guide.

Where is the model number on a Timex watch?

On the back. Timex's repair form lists three codes on the caseback: the style number (six or nine characters, as in T00000 or TW0000000), a model number made of M and three more characters (such as M921) and a two-character date code. The catch is that what Amazon calls the model number is Timex's style number: every Timex listing we track shows a style number there, and none shows the M code.

Most Timex style numbers start with TW, and listings often stretch them: most TW numbers we track are eleven characters long, two more than Timex's nine. The Timex Expedition CAT5, a 41 mm digital watch, is listed as TW4B285009J; if a long number like that finds nothing, search the first nine characters, here TW4B28500. The Timex Expedition Scout 40, a 40 mm quartz watch with a brass case and a nylon strap, is one of those listed at exactly nine, TW4B15500.

Which number on a Casio is the model number?

Casio's support pages say the model number is marked on the back cover, in letters and numbers split by dashes. Next to it, inside a small box, sits a three- or four-digit module number for the module that runs the watch, and Casio files its manuals by that number.

On Amazon, Casio numbers get messy: no single layout covers more than 11 of our 166 Casios. Casio has many model families, and each version gets its own ending; the F-91W family alone appears as F-91W-3DG, F-91WM-1BCF and F-91WM-3AEF, three different watches, and the LTP-V007D comes in five versions with five endings.

Casio's repair site asks for at least the first three characters with no spaces or dashes, so there I would type F91W; on Amazon I would search the first block, F-91W, and compare the photos of each version with my watch. The Casio F-91W-3DG is a 38.2 mm digital watch with a resin case, and the Casios we like best are in our Casio guide.

How do I read a Fossil, Guess or Anne Klein model number?

Fossil's service page says the style number is on the back of the watch, as in ES1234. In our catalog all 9 Fossil numbers starting with FS are men's watches and all 6 starting with ES are women's. The Fossil Grant FS5151 is a 44 mm men's chronograph with a blue dial on a leather strap.

On a Guess, look at the letter just before the last one or two digits: with L, 113 of 114 watches are women's; with G, 85 of 94 are men's. The Guess GW0203G5 is a 43 mm men's watch with a polycarbonate case.

Most Anne Klein numbers start with AK/ and end with four digits and four letters, and in our listings the first two of those letters match the dial: BK black and SV silver in all but one watch. GB at the end usually means a gold-colored band, as on the Anne Klein AK/3774BKGB, a 24 mm women's watch with a black dial and a gold-colored metal bracelet. Nine West uses the same layout, as in NW/2098CHGB, for nearly all its watches.

How do I identify a Hamilton, Tissot, Longines or Rado watch?

By the reference number. In our listings these four Swiss brands start it with their own initial: Hamilton, Rado and Longines follow it with eight digits, Tissot with thirteen. The same number can be written in different ways: the Tissot PR 100 listing gives it as T150.417.11.041.00 in one row and T1504171104100 in the model number row, and the Hamilton Khaki Field listing says HML-H70455133 in one row and H70455133 in the other, so drop dots, dashes and prefixes like these when you search.

The Tissot PR 100 is a 40 mm Swiss quartz chronograph with a sapphire crystal. The Hamilton Khaki Field H70455133 is a 38 mm automatic in stainless steel.

Is the serial number the same as the model number?

No. The model number names a version of a watch and is the same on every watch of that version; the serial number belongs to one single watch. Hamilton's FAQ and our reference number entry draw the same line, and Hamilton adds that a service request needs both. Timex casebacks also carry a two-character date code.

So the serial number is not the one to search for when you want the model. Amazon listings describe a model, not one particular watch, so they carry no serial number. For a watch's age or authenticity, ask the brand's own service; the warning signs of a fake are in our guide on how to spot a fake watch.

How do I find a watch on Amazon by model number?

On an Amazon listing, the model number usually sits in the product details, in the "Item model number" row, not in the title. Only one listing title in five that we track carries it: most Rado titles do, hardly any Timex title does and no Hamilton title at all. To check that a listing is your watch, read that row; the "Model name" row is a separate field, and on the Citizen Classic Corso it simply says Classic Corso.

If you bought the watch on Amazon, open it from your orders and check the product details; our product pages show the number too, under Product Details, when the listing has one. A new strap also needs the lug width, which our guide on how to change a watch strap shows you how to measure, and what a service costs is in our guide to watch servicing costs.

How we checked

The numbers come from the Bravery Watch catalog on October 22, 2026. Of the 2,749 watches we list, 2,740 have a model number in the product details of their Amazon listing, usually in the "Item model number" row, and 2,179 of those were in stock on Amazon US that day. Brand counts cover our whole catalog, including Amazon UK and Germany listings. Sizes and other specs come from each listing's spec table or title, and we matched letters and digits to dial color, band and men's or women's watches only through those tables. What each brand says about its numbers comes from its own support pages, repair forms and manuals (Citizen, Bulova, Invicta, Timex, Casio, Fossil, Hamilton, Apple and Samsung), checked on October 22 and 23, 2026. Listing data can contain mistakes, so when in doubt, ask the brand.