diff --git a/pinaxcon/templatetags/nbpy_tags.py b/pinaxcon/templatetags/nbpy_tags.py
index 16af7568bad8cef98121d1c661f82d59c9f43498..e5ccdafd3623ee0b9bae46e7b16831270132dfa4 100644
--- a/pinaxcon/templatetags/nbpy_tags.py
+++ b/pinaxcon/templatetags/nbpy_tags.py
@@ -40,5 +40,5 @@ def donation_income(context, invoice):
         elif line.product.category.name == "T-Shirt":
             rbi.append(line.total_price * fsa_rate)
 
-    donation = (invoice.value - sum(rbi))
+    donation = max(Decimal('0'), (invoice.value - sum(rbi)))
     return donation.quantize(Decimal('.01'))