diff --git a/qutebrowser/browser/downloads.py b/qutebrowser/browser/downloads.py
index 35b3d26c6..e9499600e 100644
--- a/qutebrowser/browser/downloads.py
+++ b/qutebrowser/browser/downloads.py
@@ -182,20 +182,22 @@ def transform_path(path):
     return path
 
 
-def suggested_fn_from_title(url, title=None):
+def suggested_fn_from_title(url_path, title=None):
     """Suggest a filename depending on the URL extension and page title.
+
     Args:
-        url: a string with the URL path
+        url_path: a string with the URL path
         title: the page title string
 
-    Returns None if the extension is not in the whitelist
-    or if there is no page title.
+    Return:
+        The download filename based on the title, or None if the extension is
+        not found in the whitelist (or if there is no page title).
     """
     ext_whitelist = [".html", ".htm", ".php", ""]
-    _, ext = os.path.splitext(url)
+    _, ext = os.path.splitext(url_path)
     if ext.lower() in ext_whitelist and title:
         suggested_fn = utils.sanitize_filename(title)
-        if not suggested_fn.endswith(ext):
+        if not suggested_fn.lower().endswith(ext.lower()):
             suggested_fn += ext
     else:
         suggested_fn = None
diff --git a/tests/unit/browser/webkit/test_downloads.py b/tests/unit/browser/webkit/test_downloads.py
index d22338717..c9451b949 100644
--- a/tests/unit/browser/webkit/test_downloads.py
+++ b/tests/unit/browser/webkit/test_downloads.py
@@ -31,21 +31,27 @@ def test_download_model(qapp, qtmodeltester, config_stub, cookiejar_and_cache):
 
 
 @pytest.mark.parametrize('url, title, out', [
-    ('https://qutebrowser.org/img/cheatsheet-big.png',
-     'cheatsheet-big.png (3342×2060)',
-     None),
     ('http://qutebrowser.org/INSTALL.html',
      'Installing qutebrowser | qutebrowser',
      'Installing qutebrowser _ qutebrowser.html'),
-    ('http://qutebrowser.org/INSTALL.html.html',
-     'Installing qutebrowser | qutebrowser',
+    ('http://qutebrowser.org/INSTALL.html',
+     'Installing qutebrowser | qutebrowser.html',
      'Installing qutebrowser _ qutebrowser.html'),
+    ('http://qutebrowser.org/INSTALL.HTML',
+     'Installing qutebrowser | qutebrowser',
+     'Installing qutebrowser _ qutebrowser.HTML'),
+    ('http://qutebrowser.org/INSTALL.html',
+     'Installing qutebrowser | qutebrowser.HTML',
+     'Installing qutebrowser _ qutebrowser.HTML'),
     ('http://qutebrowser.org/',
      'qutebrowser | qutebrowser',
      'qutebrowser _ qutebrowser'),
     ('https://github.com/qutebrowser/qutebrowser/releases',
      'Releases · qutebrowser/qutebrowser',
      'Releases · qutebrowser_qutebrowser'),
+    ('https://qutebrowser.org/img/cheatsheet-big.png',
+     'cheatsheet-big.png (3342×2060)',
+     None),
     ('http://qutebrowser.org/page-with-no-title.html',
      '',
      None),