diff --git a/backend/b2/b2.go b/backend/b2/b2.go
index d69c47f44..f513c7638 100644
--- a/backend/b2/b2.go
+++ b/backend/b2/b2.go
@@ -124,8 +124,13 @@ minimum size.`,
 			Default:  defaultChunkSize,
 			Advanced: true,
 		}, {
-			Name:     "disable_checksum",
-			Help:     `Disable checksums for large (> upload cutoff) files`,
+			Name: "disable_checksum",
+			Help: `Disable checksums for large (> upload cutoff) files
+
+Normally rclone will calculate the SHA1 checksum of the input before
+uploading it so it can add it to metadata on the object. This is great
+for data integrity checking but can cause long delays for large files
+to start uploading.`,
 			Default:  false,
 			Advanced: true,
 		}, {