One box, every scheme

Every other tool here asks what the thing is before it will read the number. This one does not ask. Type a serial number and it runs the number past every dating scheme on this site at once, and shows you all of them it fits.

Fitting is not the same as being. Nothing stops a television and a tractor using the same shape of serial number, and nothing stops your number fitting both. When this page returns four readings, three of them are coincidences — it has no way of telling you which three. What it can do is show you all four, and how tightly each one fits, so you can rule them out with something this page does not have: the object in your hand.

Exact fits and partial fits are not the same claim

Schemes differ enormously in how much of a number they claim. A Hull Identification Number is twelve characters with fixed fields in fixed places: it either is one or it is not. Browning’s date code is two letters at the end of a serial, which means it also fits the end of somebody else’s serial that happens to finish with two of the same letters.

Reporting both as “matched” would make the loose scheme look as confident as the strict one. So the results are split:

• Exact — the whole thing you typed is the code. The scheme claims all of it.
• Partial — the scheme found its code inside what you typed. That is how the scheme is meant to work, and it is also how a false match happens. The matched fragment is shown so you can see what it seized on.

A partial fit is worth much less than an exact one, and worth more than nothing. Both are shown; neither is presented as an answer.

What an empty result does not mean

If nothing matches, that means no scheme on this site recognises the shape of your number. It does not mean the number is undatable, and it certainly does not mean the object is not what you think it is.

This site carries the schemes it could trace to the manufacturer and reproduce honestly. That is a small fraction of the schemes that exist. Most manufacturers publish nothing at all; several publish something and forbid its reuse; and some of what is published is wrong. The pages behind each scheme say which case applies.

What is in the box

The schemes below are the ones this page runs your number past. The list is built from the decoders themselves rather than typed out here, so it cannot drift out of date the way a hand-written list would.

One tool on this site is deliberately missing from that list

The stolen-bicycle check is not in this box and will not be. It does not decode anything: it sends your serial number to Bike Index and asks whether that bike has been reported stolen. That is a useful thing and a different kind of thing, and it cannot be done without the number leaving your browser.

Putting it here would quietly break the promise in the next section, for the sake of tidiness. So it stays on its own page, where the warning sits above the input and sending the number is something you choose.

This page sends nothing anywhere

The number you type is read by JavaScript in your own browser and never leaves it. There is no request, no logging and no record. You can disconnect from the network and this page will work exactly as well.

How this is put together, and why that matters

Every scheme here is the same code the scheme’s own page runs. Not a copy of it — the same file. That was the whole difficulty in building this page, and it is worth saying why it mattered.

The easy way to build a box like this is to copy every decoder on the site into one more page. It works immediately and it rots immediately: the day somebody corrects a scheme on its own page, the copy here keeps giving the old answer, gives it confidently, and nothing on the site ever compares the two. A wrong answer that agrees with itself is the hardest kind to find.

So the decoders were moved out of the pages into shared files that both the pages and this box load. There is exactly one copy of each scheme. If a correction lands, it lands in both places because there is only one place.