diff --git a/misc-scripts/surgery/SeqStoreConverter/BasicConverter.pm b/misc-scripts/surgery/SeqStoreConverter/BasicConverter.pm
index 20c128855c7c8ff92c2bc30035776d999827fa61..2b194ca8c9d223b2e99ca5b7de615a230a990242 100644
--- a/misc-scripts/surgery/SeqStoreConverter/BasicConverter.pm
+++ b/misc-scripts/surgery/SeqStoreConverter/BasicConverter.pm
@@ -374,7 +374,7 @@ sub supercontig_to_seq_region {
 
   my $select_sth = $dbh->prepare
     ("SELECT superctg_name, " .
-     "MAX(superctg_end)-MIN(superctg_start)+1 AS length " .
+     "MAX(superctg_end) AS length " .
      "FROM $source.assembly " .
      "GROUP BY superctg_name");