diff --git a/tsdb/docs/format/head_chunks.md b/tsdb/docs/format/head_chunks.md
index ed138f4b6..813d4008c 100644
--- a/tsdb/docs/format/head_chunks.md
+++ b/tsdb/docs/format/head_chunks.md
@@ -8,7 +8,7 @@ in-file offset (lower 4 bytes) and segment sequence number (upper 4 bytes).
 
 ```
 ┌──────────────────────────────┐
-│  magic(0x85BD40DD) <4 byte>  │
+│  magic(0x0130BC91) <4 byte>  │
 ├──────────────────────────────┤
 │    version(1) <1 byte>       │
 ├──────────────────────────────┤