Free tool
ISWC Code Validator
Validate and decode any ISWC code instantly. Checks format, verifies the check digit, and explains the difference between compositions and recordings.
ISWC format reference
Work type prefix · char 1
T indicates the work is a musical composition (the only currently assigned work type). This distinguishes ISWC from ISRC, which identifies recordings rather than compositions.
Work number · chars 2–10
A 9-digit unique number assigned by CISAC to the musical work at the point of registration. Unlike an ISRC, an ISWC identifies the composition itself — not any specific recording of it.
Check digit · char 11
A single verification digit computed from the preceding 10 characters using the ISO 15707 algorithm. It detects transcription errors — a mismatch means the ISWC was entered incorrectly.
Need your compositions registered?
Unregistered compositions cannot collect mechanical or performance royalties. Our catalog assessment identifies every composition in your catalog that is missing an ISWC and gets them registered with CISAC-affiliated societies.
What is an ISWC code?
An ISWC (International Standard Musical Work Code) is a globally unique 11-character identifier assigned to a musical composition — the underlying song as written, not any specific recording of it. Defined by ISO 15707 and administered by CISAC, it is the primary mechanism by which collecting societies identify compositions and distribute mechanical and performance royalties.
When PRS, ASCAP, SACEM, GEMA, or any other collecting society pays out a royalty for a song being played on radio, streamed, or performed live, that payment is tied to the composition's ISWC. Without one, the income cannot be attributed to the correct composition — and often goes unmatched, or is paid into a pool distributed to registered works.
ISWC vs ISRC — what is the difference?
An ISWC identifies the composition (the song as written by its authors), while an ISRC identifies a specific recording of that composition. A single composition can have dozens of recordings — the original studio version, a live recording, a remix — each with its own ISRC, but all linked to the same ISWC.
Both codes work together to ensure complete royalty collection. The ISRC routes master recording royalties to the rights holder. The ISWC routes publishing royalties (mechanical and performance) to the songwriter and publisher. Missing either means money stops flowing to the right party.