diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index 36fa002b0caf..decd4774042c 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -77,10 +77,10 @@ def __init__(self):
 
 
 def _get_papertype(w, h):
-    for key, (pw, ph) in sorted(papersize.items(), reverse=True):
+    for key, (pw, ph) in sorted(papersize.items(), key=lambda v: v[1]):
         if key.startswith('l'):
             continue
-        if w < pw and h < ph:
+        if w <= pw and h <= ph:
             return key
     return 'a0'