diff --git a/library/src/calculator_functions.cpp b/library/src/calculator_functions.cpp
index 65f44dd..ad95a9c 100644
--- a/library/src/calculator_functions.cpp
+++ b/library/src/calculator_functions.cpp
@@ -200,6 +200,67 @@ uint32_t Calculator::GetCostFromDuration(Configuration * cfg,
 }
 
 
+CalcState Calculator::isParkingAllowed(Configuration const *cfg, QDateTime const &start) {
+    static const PaymentMethod paymentMethodId = Utilities::getPaymentMethodId(cfg);
+
+    if (paymentMethodId == PaymentMethod::Steps) {
+        int const weekdayId = start.date().dayOfWeek();
+        BusinessHours businessHours = Utilities::getBusinessHours(cfg, paymentMethodId);
+        if (businessHours == BusinessHours::OnlyWeekDays) {
+            if (weekdayId != (int)Qt::Saturday && weekdayId != (int)Qt::Sunday) { // e.g. Neuhauser, Linsinger Maschinenbau (741)
+                if (cfg->WeekDaysWorktime.count(weekdayId) > 0) {
+                    using WTIterator = std::multimap<int, ATBWeekDaysWorktime>::const_iterator;
+                    std::pair<WTIterator, WTIterator> p = cfg->WeekDaysWorktime.equal_range(weekdayId);
+
+                    for (WTIterator itr = p.first; itr != p.second; ++itr) {
+                        QTime const &from = Utilities::WeekDaysWorkTimeFrom(itr);
+                        QTime const &until = Utilities::WeekDaysWorkTimeUntil(itr);
+                        QTime const &startTime = start.time();
+                        if (from > startTime) {
+                            return CalcState(CalcState::State::OUTSIDE_ALLOWED_PARKING_TIME,
+                                QString("%1 < %2").arg(from.toString(Qt::ISODate))
+                                                  .arg(startTime.toString(Qt::ISODate)), from, until);
+                        } else
+                        if (startTime >= until) {
+                            return CalcState(CalcState::State::OUTSIDE_ALLOWED_PARKING_TIME,
+                                QString("%1 >= %2").arg(startTime.toString(Qt::ISODate))
+                                                   .arg(until.toString(Qt::ISODate)), from, until);
+                        }
+                        return CalcState(CalcState::State::SUCCESS,
+                                         "PARKING ALLOWED", from, until);
+                    }
+                }
+            }
+        } else
+        if (businessHours == BusinessHours::AllDaysWithRestrictedHours) { // e.g. for Neuhauser, NAZ (744)
+            if (cfg->WeekDaysWorktime.count(weekdayId) > 0) {
+                using WTIterator = std::multimap<int, ATBWeekDaysWorktime>::const_iterator;
+                std::pair<WTIterator, WTIterator> p = cfg->WeekDaysWorktime.equal_range(weekdayId);
+
+                for (WTIterator itr = p.first; itr != p.second; ++itr) {
+                    QTime const &from = Utilities::WeekDaysWorkTimeFrom(itr);
+                    QTime const &until = Utilities::WeekDaysWorkTimeUntil(itr);
+                    QTime const &startTime = start.time();
+                    if (from > startTime) {
+                        return CalcState(CalcState::State::OUTSIDE_ALLOWED_PARKING_TIME,
+                            QString("%1 < %2").arg(from.toString(Qt::ISODate))
+                                              .arg(startTime.toString(Qt::ISODate)), from, until);
+                    } else
+                    if (startTime >= until) {
+                        return CalcState(CalcState::State::OUTSIDE_ALLOWED_PARKING_TIME,
+                            QString("%1 >= %2").arg(startTime.toString(Qt::ISODate))
+                                               .arg(until.toString(Qt::ISODate)), from, until);
+                    }
+                    return CalcState(CalcState::State::SUCCESS,
+                                     "PARKING ALLOWED", from, until);
+                }
+            }
+        }
+    }
+
+    return CalcState(CalcState::State::OUTSIDE_ALLOWED_PARKING_TIME, "UNKNOWN ERROR",
+                     QTime(), QTime());
+}
 
 
 ///////////////////////////////////////