diff --git a/library/include/mobilisis/calculate_price.h b/library/include/mobilisis/calculate_price.h
index 6a6040e..483825b 100644
--- a/library/include/mobilisis/calculate_price.h
+++ b/library/include/mobilisis/calculate_price.h
@@ -207,7 +207,8 @@ int CALCULATE_LIBRARY_API get_maximal_parkingtime(Configuration const *cfg,
 
 int CALCULATE_LIBRARY_API get_minimal_parkingprice(Configuration *cfg,
                                                    PERMIT_TYPE permitType = PERMIT_TYPE::SHORT_TERM_PARKING,
-                                                   int paymentOptionIndex=0);
+                                                   int paymentOptionIndex = 0,
+                                                   QDateTime const &start = QDateTime::currentDateTime());
 
 int CALCULATE_LIBRARY_API get_maximal_parkingprice(Configuration *cfg,
                                                    PERMIT_TYPE permitType = PERMIT_TYPE::SHORT_TERM_PARKING,