diff --git a/cmd/restic/cmd_prune.go b/cmd/restic/cmd_prune.go
index c3c135836..676166f94 100644
--- a/cmd/restic/cmd_prune.go
+++ b/cmd/restic/cmd_prune.go
@@ -71,7 +71,7 @@ func addPruneOptions(c *cobra.Command) {
 	f.StringVar(&pruneOptions.MaxUnused, "max-unused", "5%", "tolerate given `limit` of unused data (absolute value in bytes with suffixes k/K, m/M, g/G, t/T, a value in % or the word 'unlimited')")
 	f.StringVar(&pruneOptions.MaxRepackSize, "max-repack-size", "", "maximum `size` to repack (allowed suffixes: k/K, m/M, g/G, t/T)")
 	f.BoolVar(&pruneOptions.RepackCachableOnly, "repack-cacheable-only", false, "only repack packs which are cacheable")
-	f.BoolVar(&pruneOptions.RepackSmall, "repack-small", false, "repack too small packs")
+	f.BoolVar(&pruneOptions.RepackSmall, "repack-small", false, "repack pack files below 80%% of target pack size")
 	f.BoolVar(&pruneOptions.RepackUncompressed, "repack-uncompressed", false, "repack all uncompressed data")
 }