diff --git a/fhem/CHANGED b/fhem/CHANGED
index 5c7626c3a..862bb8672 100644
--- a/fhem/CHANGED
+++ b/fhem/CHANGED
@@ -1,5 +1,6 @@
 # Add changes at the top of the list. Keep it in ASCII, and 80-char wide.
 # Do not insert empty lines here, update check depends on it.
+ - feature: 57_Calendar: new attribute delay
  - feature: 72_XiaomiDevice: supporting EvpHumidifier and AirPurifier3H
  - remove:  98_DSBMobile: removed due to unavailability of API
  - feature: 73_DoorBird: ftui image history as links
diff --git a/fhem/FHEM/57_Calendar.pm b/fhem/FHEM/57_Calendar.pm
index d73738ae8..9d35545bb 100644
--- a/fhem/FHEM/57_Calendar.pm
+++ b/fhem/FHEM/57_Calendar.pm
@@ -1722,6 +1722,7 @@ sub Calendar_Initialize($) {
   $hash->{NotifyFn}= "Calendar_Notify";
   $hash->{AttrList}=  "update:none,onUrlChanged ".
                       "synchronousUpdate:0,1 ".
+                      "delay " .
                       "removevcalendar:0,1 " .
                       "ignoreCancelled:0,1 ".
                       "SSLVerify:0,1 ".
@@ -1845,7 +1846,7 @@ sub Calendar_Notify($$)
   # update calendar after initialization or change of configuration
   # wait 10 to 29 seconds to avoid congestion due to concurrent activities
   Calendar_DisarmTimer($hash);
-  my $delay= 10+int(rand(20));
+  my $delay= AttrVal($name, "delay", 10+int(rand(20)));
 
   Log3 $hash, 5, "Calendar $name: FHEM initialization or rereadcfg triggered update, delay $delay seconds.";
   InternalTimer(time()+$delay, "Calendar_Wakeup", $hash, 0) ;
@@ -3676,6 +3677,13 @@ sub CalendarEventsAsHtml($;$) {
         If this attribute is set to <code>none</code>, the calendar will not be updated at all.
         </li><p>
 
+    <li><code>delay &lt;time&gt;</code><br>
+        The waiting time in seconds after the initialization of FHEM or a configuration change before 
+        actually retrieving the calendar from its source. If not set, a random time between 10 and 29 
+        seconds is chosen. When several calendar devices are defined, staggered delays reduce
+        load error rates.
+        </li><p>
+
     <li><code>removevcalendar 0|1</code><br>
         If this attribute is set to 1, the vCalendar will be discarded after the processing to reduce the memory consumption of the module.
         A retrieval via <code>get &lt;name&gt; vcalendar</code> is then no longer possible.
@@ -4279,7 +4287,7 @@ sub CalendarEventsAsHtml($;$) {
   <br>
 
   <a name="Calendarattr"></a>
-  <b>Attributes</b>
+  <b>Attribute</b>
   <br><br>
   <ul>
     <li><code>defaultFormat &lt;formatSpec&gt;</code><br>
@@ -4307,6 +4315,13 @@ sub CalendarEventsAsHtml($;$) {
         URL seit dem letzten Aufruf ver&auml;ndert hat, insbesondere nach der Auswertung von wildcards im define.<br/>
         </li><p>
 
+    <li><code>delay &lt;time&gt;</code><br>
+        Wartezeit in Sekunden nach der Initialisierung von FHEM oder einer Konfigurations&auml;nderung bevor
+        der Kalender tats&auml;chlich von der Quelle geladen wird. Wenn nicht gesetzt wird eine
+        Zufallszeit zwischen 10 und 29 Sekunden gew&auml;hlt. Wenn mehrere Kalender definiert sind, f&uuml;hren
+        gestaffelte Wartezeiten zu einer Verminderung der Ladefehleranf&auml;lligkeit.
+        </li><p>
+
     <li><code>removevcalendar 0|1</code><br>
 		Wenn dieses Attribut auf 1 gesetzt ist, wird der vCalendar nach der Verarbeitung verworfen,
 		gleichzeitig reduziert sich der Speicherverbrauch des Moduls.