diff --git a/bookwyrm/templates/snippets/form_rate_stars.html b/bookwyrm/templates/snippets/form_rate_stars.html
index dfd5a758..302f181e 100644
--- a/bookwyrm/templates/snippets/form_rate_stars.html
+++ b/bookwyrm/templates/snippets/form_rate_stars.html
@@ -1,5 +1,6 @@
 {% spaceless %}
 {% load i18n %}
+{% load stars %}
 
 <div class="
     field is-grouped
@@ -24,7 +25,7 @@
             class="is-sr-only"
             for="{{ type|slugify }}_book{{ book.id }}_star_{{ forloop.counter0 }}_half"
         >
-                {% blocktranslate trimmed count rating=forloop.counter0 with half_rating=forloop.counter0|add:""|add:"0.5" %}
+                {% blocktranslate trimmed count rating=forloop.counter0 with half_rating=forloop.counter0|half_star %}
                     {{ half_rating }} star
                 {% plural %}
                     {{ half_rating }} stars
diff --git a/bookwyrm/templatetags/stars.py b/bookwyrm/templatetags/stars.py
new file mode 100644
index 00000000..d08dd8ef
--- /dev/null
+++ b/bookwyrm/templatetags/stars.py
@@ -0,0 +1,11 @@
+""" template filters """
+from django import template
+
+
+register = template.Library()
+
+
+@register.filter(name="half_star")
+def get_half_star(value):
+    """one of those things that's weirdly hard with templates"""
+    return f"{value}.5"