diff --git a/reference/forms/types/collection.rst b/reference/forms/types/collection.rst
index ba61e8ca3c3..65e89202c94 100644
--- a/reference/forms/types/collection.rst
+++ b/reference/forms/types/collection.rst
@@ -182,7 +182,7 @@ And update the template as follows:
         <ul id="email-fields-list"
             data-prototype="{{ form_widget(form.emails.vars.prototype)|e }}"
             data-widget-tags="{{ '<li></li>'|e }}"
-            data-widget-counter="{{ form.children|length }}">
+            data-widget-counter="{{ form.emails|length }}">
         {% for emailField in form.emails %}
             <li>
                 {{ form_errors(emailField) }}