diff --git a/tsdb/compact.go b/tsdb/compact.go
index 042191875..79ec8f60f 100644
--- a/tsdb/compact.go
+++ b/tsdb/compact.go
@@ -482,7 +482,7 @@ func (c *LeveledCompactor) compact(dest string, dirs []string, open []*Block, sh
 					"count", len(blocks),
 					"sources", fmt.Sprintf("%v", uids),
 					"duration", time.Since(start),
-					"shard", fmt.Sprintf("%d_of_%d", ix, shardCount),
+					"shard", fmt.Sprintf("%d_of_%d", ix+1, shardCount),
 				)
 			} else {
 				allOutputBlocksAreEmpty = false
@@ -496,7 +496,7 @@ func (c *LeveledCompactor) compact(dest string, dirs []string, open []*Block, sh
 					"ulid", meta.ULID,
 					"sources", fmt.Sprintf("%v", uids),
 					"duration", time.Since(start),
-					"shard", fmt.Sprintf("%d_of_%d", ix, shardCount),
+					"shard", fmt.Sprintf("%d_of_%d", ix+1, shardCount),
 				)
 			}
 		}