Glossary · Technical
ISWC
An ISWC, International Standard Musical Work Code, is a unique identifier for a musical composition, formatted as T followed by nine digits and a check digit. It identifies the song itself across every recording of it, and is assigned by collection societies.
An ISWC identifies a composition, where an ISRC identifies a recording. One song covered by fifty artists has one ISWC and fifty ISRCs. The format is the letter T, nine digits and a check digit — for example T-123.456.789-C.
ISWCs are issued through the CISAC system by collection societies rather than by artists or distributors. In practice, an ISWC is generated when a work is registered with a society: ASCAP, BMI, SESAC or GMR on the performance side, and The MLC's registrations connect into the same identifier space. You do not buy or apply for one directly the way you can obtain an ISRC registrant code from the RIAA.
The reason to care is international matching. When usage is reported in one country and the writers are registered in another, the ISWC is the key that links them. Without it, a foreign society is matching on title and writer name, and titles are not unique — every third song is called "Home."
Because an ISWC is created by registration, having one is a signal that your composition actually exists in the system. If you look up a song of yours at The MLC or in your PRO's repertory search and there is no ISWC attached, the work is not properly registered, and streaming mechanicals reported against its recordings have nowhere to land.
The misunderstanding: confusing an ISWC with an ISRC and assuming your distributor supplied both. Distributors issue ISRCs. They do not register compositions, so they do not produce ISWCs.
If you only remember one thing: ISRC is the recording, ISWC is the song. Artist's notes, not legal advice.
Related terms
- ISRCAn ISRC, International Standard Recording Code, is a 12-character identifier assigned to a specific sound recording.
- Musical compositionA musical composition is the song itself — the melody, harmony, structure and lyrics — protected as its own copyright separate…
- The MLC (Mechanical Licensing Collective)The MLC is the non-profit organisation designated under the Music Modernization Act to administer the United States blanket…
- CISACCISAC, the International Confederation of Societies of Authors and Composers, is the global umbrella body for collection…
Answers that use this term
- ISRC vs ISWC: The Two Codes Your Song NeedsAn ISRC identifies a specific sound recording and is issued when you distribute — DistroKid, TuneCore and CD Baby assign one…
- How to Register With The MLC (Step by Step)Registering with The MLC is free. Create a member account at themlc.com, choose Self-Administered Songwriter if you control your…
- How to Fill Out a Split Sheet (With Every Field Explained)A split sheet records one song's writing shares in writing before anyone leaves the session.
Definitions on this site describe the United States system. I am an artist who has been through this, not a lawyer.
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