diff --git a/lib/behat/behat_base.php b/lib/behat/behat_base.php
index fa9e207722d..74800e75fe6 100644
--- a/lib/behat/behat_base.php
+++ b/lib/behat/behat_base.php
@@ -665,11 +665,11 @@ class behat_base extends Behat\MinkExtension\Context\RawMinkContext {
 
         switch ($windowsize) {
             case "small":
-                $width = 640;
-                $height = 480;
+                $width = 1024;
+                $height = 768;
                 break;
             case "medium":
-                $width = 1024;
+                $width = 1366;
                 $height = 768;
                 break;
             case "large":