diff --git a/src/NodaSplitTime.php b/src/NodaSplitTime.php
index 1228ffe..7623abb 100644
--- a/src/NodaSplitTime.php
+++ b/src/NodaSplitTime.php
@@ -28,9 +28,10 @@ final class NodaSplitTime {
     /**
      * Returns a single, exact date.
      *
-     * @param string $year  Year.
-     * @param string $month Month.
-     * @param string $day   Day.
+     * @param string                       $year                   Year.
+     * @param string                       $month                  Month.
+     * @param string                       $day                    Day.
+     * @param NodaTimeBeforeAfterIndicator $before_after_indicator Determines if the time is exact or before / after.
      *
      * @return NodaSplitTime
      */
@@ -296,6 +297,15 @@ final class NodaSplitTime {
     /**
      * Constructor.
      *
+     * @param string                       $start_year              Year.
+     * @param string                       $end_year                Year.
+     * @param string                       $counting_time_month     Month.
+     * @param string                       $counting_time_day       Day.
+     * @param NodaCountingTimeIndicator    $counting_time_indicator Determines if the time is BCE or CCE.
+     * @param NodaTimeBeforeAfterIndicator $before_after_indicator  Determines if the time is inexact to one direction.
+     * @param false|string                 $start_date              Start date.
+     * @param false|string                 $end_date                End date.
+     *
      * @return void
      */
     public function __construct(string $start_year, string $end_year,
@@ -379,5 +389,19 @@ final class NodaSplitTime {
             }
         }
 
+        // Validate
+        $startDateTime = MD_STD::strtotime("2000-" . substr($this->start_date, -5));
+        if (checkdate((int)date('m', $startDateTime), (int)date('d', $startDateTime), (int)date('Y', $startDateTime)) === false) {
+            throw new MDgenericInvalidInputsException("Invalid start date: " . $this->start_date);
+        }
+
+        if (!empty((int)$this->counting_time_day)) {
+            // The year 2000 is used here as it is a leap year and lots of years accepted in md are not accepted
+            // by checkdate.
+            if (checkdate((int)$this->counting_time_month, (int)$this->counting_time_day, 2000) === false) {
+                throw new MDgenericInvalidInputsException("Invalid date formed by counting time: " . $this->counting_time_month . ' -- ' . $this->counting_time_day);
+            }
+        }
+
     }
 }
diff --git a/tests/NodaTimeSplitterTest.php b/tests/NodaTimeSplitterTest.php
index cefa09c..3f03bef 100644
--- a/tests/NodaTimeSplitterTest.php
+++ b/tests/NodaTimeSplitterTest.php
@@ -550,6 +550,9 @@ final class NodaTimeSplitterTest extends TestCase {
         ];
 
         foreach ([
+            "30.02.2024",
+            "31.11.2024",
+            "31.4.2024",
             "1.2.2020-2.2.2020",
             "2020 Januar 2-2020 Februar 2",
             "2020 Januar-2020 Februar",