diff --git a/ihatemoney/templates/forms.html b/ihatemoney/templates/forms.html
index f93cfc6d..78398ce7 100644
--- a/ihatemoney/templates/forms.html
+++ b/ihatemoney/templates/forms.html
@@ -166,7 +166,9 @@
     {{ input(form.date, inline=True) }}
     {{ input(form.what, inline=True) }}
     {{ input(form.payer, inline=True, class="form-control custom-select") }}
-    {{ input(form.amount, inline=True) }}
+    <div data-toggle="tooltip" data-placement="top" title='{{ _("Simple operations are allowed, e.g. (18+36.2)/3") }}'>
+        {{ input(form.amount, inline=True) }}
+    </div>
 
     <div class="form-group row">
         <label class="col-3" for="payed_for">{{ _("For whom?") }}</label>