diff --git a/addons/web/static/src/js/views/form/form_renderer.js b/addons/web/static/src/js/views/form/form_renderer.js
index 61576832ff5..d221f93a4e8 100644
--- a/addons/web/static/src/js/views/form/form_renderer.js
+++ b/addons/web/static/src/js/views/form/form_renderer.js
@@ -15,6 +15,10 @@ var FormRenderer = BasicRenderer.extend({
         'click .o_notification_box .oe_field_translate': '_onTranslate',
         'click .oe_title, .o_inner_group': '_onClick',
     }),
+    // default col attributes for the rendering of groups
+    INNER_GROUP_COL: 2,
+    OUTER_GROUP_COL: 2,
+
     /**
      * @override
      */
@@ -387,7 +391,7 @@ var FormRenderer = BasicRenderer.extend({
         this._handleAttributes($result, node);
         this._registerModifiers(node, this.state, $result);
 
-        var col = parseInt(node.attrs.col, 10) || 2;
+        var col = parseInt(node.attrs.col, 10) || this.INNER_GROUP_COL;
 
         if (node.attrs.string) {
             var $sep = $('<tr><td colspan="' + col + '" style="width: 100%;"><div class="o_horizontal_separator">' + node.attrs.string + '</div></td></tr>');
@@ -511,7 +515,8 @@ var FormRenderer = BasicRenderer.extend({
     _renderOuterGroup: function (node) {
         var self = this;
         var $result = $('<div/>', {class: 'o_group'});
-        var colSize = Math.max(1, Math.round(12 / (parseInt(node.attrs.col, 10) || 2)));
+        var nbCols = parseInt(node.attrs.col, 10) || this.OUTER_GROUP_COL;
+        var colSize = Math.max(1, Math.round(12 / nbCols));
         if (node.attrs.string) {
             var $sep = $('<div/>', {class: 'o_horizontal_separator'}).text(node.attrs.string);
             $result.append($sep);