diff --git a/addons/web/static/src/js/view_form.js b/addons/web/static/src/js/view_form.js
index 08050c7d686..439aaf0ed89 100644
--- a/addons/web/static/src/js/view_form.js
+++ b/addons/web/static/src/js/view_form.js
@@ -2720,7 +2720,7 @@ instance.web.form.FieldTextHtml = instance.web.form.AbstractField.extend(instanc
         if (! this.get("effective_readonly")) {
             self._updating_editor = false;
             this.$textarea = this.$el.find('textarea');
-            var width = ((this.node.attrs || {}).editor_width || '100%');
+            var width = ((this.node.attrs || {}).editor_width || 'calc(100% - 4px)');
             var height = ((this.node.attrs || {}).editor_height || 250);
             this.$textarea.cleditor({
                 width:      width, // width not including margins, borders or padding