diff --git a/docs/format/chunks.md b/docs/format/chunks.md
index 3faae9b7df..df388675e3 100644
--- a/docs/format/chunks.md
+++ b/docs/format/chunks.md
@@ -2,7 +2,7 @@
 
 The following describes the format of a single chunks file, which is created in the `chunks/` directory of a block. The maximum size per segment file is 512MiB.
 
-Chunks in the files are referenced from the index by the in-file offset in the 4 LSB and the segment sequence number in the higher 4 MSBs.
+Chunks in the files are referenced from the index by uint64 composed of in-file offset (lower 4 bytes) and segment sequence number (upper 4 bytes).
 
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