diff --git a/library/include/mobilisis/calculator_functions.h b/library/include/mobilisis/calculator_functions.h
index f1b3eb9..bad0566 100644
--- a/library/include/mobilisis/calculator_functions.h
+++ b/library/include/mobilisis/calculator_functions.h
@@ -8,6 +8,7 @@ using namespace std;
 class Calculator
 {
 public:
+
 	/// <summary>
 	/// Gets duration in seconds from cost
 	/// </summary>
@@ -44,6 +45,21 @@ private:
     uint32_t GetCostFromDuration(Configuration *cfg, QDateTime const &start, quint64 durationMinutes) const;
     uint32_t GetCostFromDuration(Configuration *cfg, QDateTime const &start, QDateTime const &end) const;
 
+    PaymentMethod getPaymentMethodId(Configuration const *cfg);
+    int getMinimalParkingTime(Configuration const *cfg, PaymentMethod methodId);
+    int getMaximalParkingTime(Configuration const *cfg, PaymentMethod methodId);
+
+    uint32_t private_GetCostFromDuration(Configuration const* cfg,
+                                         QDateTime const &start,
+                                         QDateTime &end,
+                                         int durationMinutes,
+                                         bool nextDay = false,
+                                         bool prepaid = false,
+                                         bool overtime = false);
+
+    bool checkDurationMinutes(bool overTime,
+                              int minParkingTime, int maxParkingTime,
+                              int durationMinutes);
 
     //
     uint32_t GetPriceForTimeStep(Configuration *cfg, int timeStep) const;