Recordz
What is a matrix number on a vinyl record?
A matrix number is the code stamped or hand-etched into a record's dead wax, the smooth area between the last groove and the label. It usually combines a catalog-style number, a side identifier and a cut number, and it may sit alongside plant, mastering-engineer, mother and stamper marks. Collectors use these markings to tell apart pressings that otherwise look identical.
Where to find it
Tilt the record under a bright light and look in the run-out area, also called the dead wax or matrix area. Each side has its own markings. Some are machine-stamped, some hand-etched, and many records have both. The matrix number is often printed on the label too, usually in small type and different on each side, which is how you tell it from the catalog number, which is normally the same on both sides.
What the parts mean
The exact layout varies by label, country and era. On older EMI UK pressings, documented in detail by Beatles collectors, the parts sit at fixed positions around the label:
| Part | Example | Meaning |
|---|---|---|
| Matrix number | YEX 178 | Identifies the side's master |
| Cut number | -2 | Second lacquer cut of that side |
| Mother number | 1 | Which metal mother the stamper came from |
| Stamper code | GT | Stamper 19, in EMI's letter code |
| Engineer or studio mark | RVG, STERLING | Who or where it was cut |
| Plant mark | Plastylite "ear" | Where it was pressed |
On EMI records the matrix and cut usually sit at 6 o'clock, the mother number at 9 and the stamper code at 3. Other markings vary: Rudy Van Gelder's "RVG" appears on many Blue Notes he mastered, and "STERLING" marks records mastered at Sterling Sound.
How the markings get there
A record side starts as a lacquer cut on a lathe. A plating plant then makes a metal master from it, then mothers from the master, then stampers from each mother, and the stampers press the records. 8481 Melrose's runout guide notes that markings can be added at any of these stages, but most are made in the lacquer, by the cutting engineer or by the plating plant on intake.
That's why some characters look different. The "Secrets of the dead-wax" guide at pspatialaudio.com points out that stamper codes are usually raised slightly from the surface when viewed in a raking light, while lacquer and mother numbers are cut into it.
Label-specific codes
Some companies hid numbers in words. EMI used GRAMOPHLTD, where G=1, R=2, A=3, M=4, O=5, P=6, H=7, L=8, T=9 and D=0, so "GT" is stamper 19. Decca used BUCKINGHAM in the same way, from B=1 to M=0. Sources disagree on when EMI dropped the cipher: one Beatles matrix guide dates the change to late 1980, another collectors' guide says the late 1980s.
Some engineers left messages. Wikipedia notes that UK cutting engineer George Peckham often signed his work "Porky" or "A Porky Prime Cut", sometimes with jokes about the record.
What a matrix number can't tell you
A "-1" cut number is not proof of a first pressing. Big releases were often cut several times at once for different plants, a first cut could be rejected, and Wikipedia notes that a reissue that's recut may start again at 1. A collectors' site on Rolling Stones Decca pressings also reports that mixed cut and stamper combinations on the same copy are common, because plants paired stampers as needed.
On Discogs, runouts are entered verbatim as a single string per side, with the capitalization found on the record and a single space for any gap, and minor differences are listed as numbered variants.
Matrix number FAQ
Is the matrix number the same as the catalog number?
No. The catalog number identifies the release and is usually the same on both sides; the matrix number identifies each side's master and differs between sides, although it often resembles the catalog number.
Does a lower cut number mean better sound?
Not necessarily. Recuts were a normal part of production, and a later cut isn't automatically further from the master. A lower number mostly signals an earlier and sometimes rarer copy.
What's the difference between stamped and etched?
Stamped markings are made with metal punches and look uniform; etched markings are written by hand and look like handwriting. Guidance for Discogs' runout contributors notes that, for some records, which parts are stamped or etched helps identify the pressing.
Why is there a message in my runout?
Usually it was added by the cutting engineer, though Wikipedia notes that the "Do What Thou Wilt" inscription on some copies of Led Zeppelin's "Immigrant Song" is believed to have been requested by the band.
Do CDs have matrix numbers?
Yes. CDs carry codes on the inner ring near the hub, and since 1994 many also carry IFPI SID codes identifying the mastering and mould equipment.
Last updated September 30, 2026.
Sources: Wikipedia, Matrix number; Discogs, Database Guidelines 5: Barcodes & Identifiers; Discogs forum, guidance for the runout lists; Beatles Shootouts, EMI UK matrices guide; Secrets of the dead-wax; 8481 Melrose, Reading Runouts; Stones on Decca, matrix numbers; LondonJazzCollector, the Blue Note labels.
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