diff --git a/packages/tag-release.nix b/packages/tag-release.nix
index 0bd612b6..410be9e9 100644
--- a/packages/tag-release.nix
+++ b/packages/tag-release.nix
@@ -7,7 +7,7 @@ writeShellApplication {
 
   text = ''
     commit_sha="''${1:-HEAD}"
-    tag="$(date '+%Y-%m-%d-%H.%M.%S')"
+    tag="$(date '+%Y%m%d%R%S' | sed "s/://g")"
 
     echo "Tagging commit $(git rev-parse "''${commit_sha}") as ''${tag}."
     echo ""