How to read a Louis Vuitton date code — and why it proves less than you think

If a bag was made between 2007 and early 2021, its date code is two letters followed by four digits. The letters are the factory. The digits are the week and year, interleaved: the first and third digits give the week, the second and fourth give the year. So SD2119 reads as week 21 of 2019, made at the SD facility. That is the whole system. It takes ten seconds once you know the order.

What most listings get wrong is what follows. A correct date code does not mean a bag is authentic. Counterfeiters copy date codes perfectly, and have for years. The code is a data point, not a verdict.

The formats, by era

2007 to early 2021. Two letters, four digits, interleaved as above. This is the format you will meet most often in resale, and the only one that decodes cleanly without cross-referencing.

Pre-2007. Formats vary — three or four digits, letters in inconsistent positions, some early bags with no code at all. Decoding these reliably means checking the code against the model, the hardware style, and the canvas treatment together. A bag from 1994 with a format that "looks wrong" is often correct for its year. This is where inexperienced sellers most often mislabel a genuine bag as suspicious, and where inexperienced buyers most often walk away from a good piece.

March 2021 onward. Louis Vuitton began phasing out heat-stamped date codes and embedding an RFID microchip instead. The transition was gradual, so bags from late 2020 and early 2021 vary — some have codes, some have chips, and both can be correct.

Where to look

Placement moves by model, which is why people conclude a bag "has no date code" when it does. Check:

• Interior leather tabs, often tucked behind a pocket
• Sewn into a seam so only the stamped edge is visible
• On a small leather patch inside a zipped pocket
• Occasionally on a hangtag rather than the bag itself

On a Speedy, look inside the interior pocket. On a Neverfull, check the seam near the top corner. If you cannot find it after a careful search, ask the seller for a photograph of it specifically — an honest seller will send one within the hour.

The microchip, and a claim to be sceptical of

The chip introduced in 2021 is an RFID tag used for the house's own inventory and logistics. It is not a consumer authentication tool.

There is no public Louis Vuitton app that verifies a bag by scanning its chip. If a seller tells you they scanned the chip and it "came back authentic," they are either mistaken or hoping you do not know better. Treat that claim as a reason to ask more questions, not fewer.

This matters more each year. As chipped bags age into the resale market, the absence of a readable date code will be normal — and the space where a verification story used to sit will get filled with invented ones.

What a date code actually tells you

Three useful things.

Whether the age matches the story. A seller describing a bag as "from the early 2000s" whose code decodes to 2015 has either misremembered or is guessing. Neither is fatal, but it tells you how much of the rest of the description to trust.

Whether the format matches the era. A 2007-onward two-letter code on a bag whose hardware and canvas are clearly 1990s is a genuine red flag — not because the code alone decides anything, but because the combination is impossible.

Whether wear matches age. A code reading 2019 on a bag with heavy handle patina and rubbed corners suggests hard use in a short window. Not a problem in itself, but it should be reflected in both the description and the price.

What it does not tell you

Authenticity. Say it plainly: the code is the easiest element of a bag to copy, because it is a heat stamp on leather rather than a construction detail. A questionable piece can still have a plausible code in the right place in the right format.

Real authentication happens elsewhere — in stitch count and angle, in the weight and finish of hardware, in how the canvas pattern aligns across seams, in the smell and grain of the leather, in the way the piece is assembled. Those are expensive to reproduce well and hard to reproduce consistently.

How we use them

At Fowlier, the date code is the first thing we record and the last thing we rely on. Where a piece is independently authenticated, that is done by a trusted third-party service examining the material itself rather than stamped text. The code goes in the listing because you deserve to know the age of what you are buying, and because a seller who publishes it is a seller who has looked.

If a listing anywhere shows you a date code as its proof of authenticity, that is the moment to ask what else they checked.

A short checklist

• Find the code and photograph it yourself, or ask for a clear photograph
• Decode it: first and third digits are the week, second and fourth the year
• Check the decoded year against the model's production era
• Check it against the seller's description of the bag's age
• Check wear against age
• Then set it aside and evaluate the bag itself

The code is where authentication starts. Anyone treating it as where authentication ends is telling you something about how carefully they work.

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