diff --git a/beets/library/models.py b/beets/library/models.py
index 7d81720142..623ccacaa2 100644
--- a/beets/library/models.py
+++ b/beets/library/models.py
@@ -1223,6 +1223,7 @@ def destination(
         relative_to_libdir: bool = False,
         basedir: bytes | None = None,
         path_formats: list[PathFormat] | None = None,
+        extension: str | None = None,
     ) -> bytes:
         """Return the path in the library directory designated for the item
         (i.e., where the file ought to be).
@@ -1262,7 +1263,9 @@ def destination(
             subpath = util.asciify_path(subpath)
 
         lib_path_str, fallback = util.legalize_path(
-            subpath, self.db.replacements, self.filepath.suffix
+            subpath,
+            self.db.replacements,
+            f".{extension}" if extension else self.filepath.suffix,
         )
         if fallback:
             # Print an error message if legalization fell back to
diff --git a/beetsplug/convert.py b/beetsplug/convert.py
index 92e4f2f8f4..ca34f145e1 100644
--- a/beetsplug/convert.py
+++ b/beetsplug/convert.py
@@ -394,8 +394,18 @@ def should_transcode(self, item: Item) -> bool:
         return self.fmt != item.format.lower()
 
     def get_item_destination(self, item: Item) -> bytes:
+        extension = (
+            os.fsdecode(self.command.ext)
+            if (
+                self.should_transcode(item)
+                and not self.config["keep_new"].get(bool)
+            )
+            else None
+        )
         return item.destination(
-            basedir=self.dest, path_formats=self.path_formats
+            basedir=self.dest,
+            path_formats=self.path_formats,
+            extension=extension,
         )
 
     @pipeline.mutator_stage
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 8316ff9a3c..de39d47f5b 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -30,6 +30,8 @@ Bug fixes
 - :doc:`plugins/lyrics`: ``beet lyrics`` no longer crashes with an
   ``AttributeError`` on tracks that have no stored lyrics when ``force`` is
   enabled; a missing lyrics body is now treated as empty text. :bug:`6860`
+- Fixed convert plugin not taking into account the new format when determining
+  the target path. :bug:`1360`
 
 ..
     For plugin developers