About Check My Guitar

Why this exists

Serial number lookups are not hard to find. What is hard to find is one that tells you how confident it is, where its information came from, and what it cannot establish.

Most tools return a year and stop. That is a problem, because a great many serial numbers do not support a single year. Gibson Custom Shop numbers record one digit of the year, so the same pattern repeats every decade. Fender ran the alphabet twice on its Japanese instruments. Fender’s own tables give two-year ranges because necks and bodies were dated separately. A tool that resolves all of that into one confident number is not being helpful; it is discarding information you needed.

The other problem is authenticity. People arrive at these tools wanting to know whether a guitar is real, and a serial number cannot answer that question. Any tool that lets you leave believing it has is doing harm, because the sums involved are not small.

What it does

Enter a serial number and, if you know it, the manufacturer. You get the likely production period, the factory and country where the format records them, a breakdown of how the number was read, a confidence level with the reasons behind it, every alternative reading that remains plausible, the sources the rule depends on, and an explicit list of what the result does not establish.

It currently covers 20 serial formats across five manufacturer families, backed by 9 references, alongside 22 guides covering the formats in more depth.

How it is built

The decoder is separate from the interface. Serial rules live in typed files that carry their own sources, caveats and test examples, and the test suite walks the whole catalogue before every deployment — a rule missing a source, a review date or a negative test example fails the build rather than shipping.

The decoder runs in your browser. That is a privacy decision before it is a performance one: the serial you type never reaches a server, never lands in a log, and never appears in a page address. It also means the tool works on a bad connection and results appear instantly.

What it will not do

It will not invent a format, a factory code or a date. It will not guess a model. It will not estimate a value. It will not tell you an instrument is authentic, because a serial number cannot support that and pretending otherwise would make it dangerous.

When Martin’s published table runs out, we say so and stop rather than extrapolating a year from production volumes. The extrapolated number would look precise and mean nothing.

Adding manufacturers

Taylor, Ibanez, Yamaha, Gretsch, PRS, Jackson, Schecter, Guild, Washburn, Alvarez, ESP, G&L, Peavey and Charvel are all planned. Each will be added only once its formats can be sourced and tested to the same standard as the existing five.

Adding brands by guessing at their formats would make the manufacturer list longer and every result on the site less trustworthy. Five well is better than fifteen badly.

Independence

Check My Guitar is independent. It is not affiliated with, endorsed by or connected to Gibson, Epiphone, Fender, Squier, C.F. Martin & Co. or any other manufacturer. Manufacturer names appear here only to identify the instruments they made, and no manufacturer logo or trademark artwork is reproduced anywhere on the site.

Read next

• Methodology — how rules are sourced, how confidence is scored, and what happens when several readings are plausible.
• Sources — every reference, labelled by type, with the rules that depend on it.
• Disclaimer — what this reference is and is not.
• Privacy — how serial numbers and submissions are handled.