diff --git a/app/service/rest.py b/app/service/rest.py
index 275f60e95..fb18d4a6d 100644
--- a/app/service/rest.py
+++ b/app/service/rest.py
@@ -1153,9 +1153,19 @@ def get_service_message_ratio():
     messages_sent = dao_get_notification_count_for_service_message_ratio(
         service_id, current_year
     )
+    messages_remaining = my_service.total_message_limit - messages_sent
+
+    if my_service.total_message_limit - messages_sent < 0:
+        raise Exception(
+            f"Math error get_service_message_ratio(), \
+                        total {my_service.total_message_limit} \
+                        messages_sent {messages_sent} remaining {messages_remaining} \
+                        service_id {service_id} current_year {current_year}"
+        )
 
     return {
         "messages_sent": messages_sent,
+        "messages_remaining": messages_remaining,
         "total_message_limit": my_service.total_message_limit,
     }, 200