diff --git a/library/src/calculator_functions.cpp b/library/src/calculator_functions.cpp
index 39c4994..39116e9 100644
--- a/library/src/calculator_functions.cpp
+++ b/library/src/calculator_functions.cpp
@@ -204,7 +204,9 @@ std::string Calculator::GetDurationFromCost(Configuration* cfg,
             return GetDurationFromCost(cfg, payment_option, inputDate.toString(Qt::ISODate).toStdString().c_str(), money_left ,true, prepaid);
         }
 
+        if(money_left > 1)
         inputDate = inputDate.addSecs(60);
+
         if(price_per_unit > 0) total_duration_min +=1;
         money_left -= price_per_unit;