diff --git a/src/www/interfaces.php b/src/www/interfaces.php
index 69b991945..b7dab955d 100644
--- a/src/www/interfaces.php
+++ b/src/www/interfaces.php
@@ -2512,24 +2512,24 @@ include("head.inc");
                             <select name="dhcp6-ia-pd-len" class="selectpicker" data-style="btn-default" id="dhcp6-ia-pd-len">
 <?php
                             foreach(array(
-                              'none' => gettext('None'),
-                              16 => '48',
-                              15 => '49',
-                              14 => '50',
-                              13 => '51',
-                              12 => '52',
-                              11 => '53',
-                              10 => '54',
-                              9 => '55',
-                              8 => '56',
-                              7 => '57',
-                              6 => '58',
-                              5 => '59',
-                              4 => '60',
-                              3 => '61',
-                              2 => '62',
-                              1 => '63',
                               0 => '64',
+                              1 => '63',
+                              2 => '62',
+                              3 => '61',
+                              4 => '60',
+                              5 => '59',
+                              6 => '58',
+                              7 => '57',
+                              8 => '56',
+                              9 => '55',
+                              10 => '54',
+                              11 => '53',
+                              12 => '52',
+                              13 => '51',
+                              14 => '50',
+                              15 => '49',
+                              16 => '48',
+                              'none' => gettext('None'),
                             ) as $bits => $length): ?>
                               <option value="<?=$bits;?>" <?= "{$bits}" === "{$pconfig['dhcp6-ia-pd-len']}" ? 'selected="selected"' : '' ?>>
                                   <?=$length;?>