diff --git a/_plugins/events_to_ics.rb b/_plugins/events_to_ics.rb
index 938439d..6891489 100644
--- a/_plugins/events_to_ics.rb
+++ b/_plugins/events_to_ics.rb
@@ -16,8 +16,8 @@ module Jekyll
 
       events.each do |event|
         title = event.data['title']
-        date = event.data.dig('event', 'date') || event.data['event_date']
-        duration = event.data.dig('event', 'duration')
+        start_date = event.data.dig('event', 'start') || event.data['event_date']
+        end_date = event.data.dig('event', 'end') || event.data['event_date']
         organizer = event.data.dig('event', 'organizer') || default_organizer
         location = event.data.dig('event', 'location') || default_location
 
@@ -31,12 +31,15 @@ module Jekyll
 
         # Create new event and set its properties
         ical_event = Icalendar::Event.new
-        if duration
-          ical_event.dtstart = date
-          ical_event.dtend = date + duration.to_i * 60
+        if start_date > end_date
+          raise StandardError.new "#{File.basename(event.path)}: Start date must not be greater than end date"
+        end
+        if start_date < end_date
+          ical_event.dtstart = start_date
+          ical_event.dtend = end_date
         else
-          ical_event.dtstart = Icalendar::Values::Date.new(date)
-          ical_event.dtend = Icalendar::Values::Date.new(date)
+          ical_event.dtstart = Icalendar::Values::Date.new(start_date)
+          ical_event.dtend = Icalendar::Values::Date.new(end_date)
         end
         ical_event.summary = title
         ical_event.description = description
diff --git a/calendar-data.html b/calendar-data.html
index 1e2ca8b..0a1c3b5 100644
--- a/calendar-data.html
+++ b/calendar-data.html
@@ -6,10 +6,13 @@ permalink: /calendar-data/
 
 [
 {% for event in site.events %}
+	{% assign start = event.event.start | default: event.event_date %}
+	{% assign end = event.event.end | default: start %}
 	{
 		"title":"{{event.title}}",
-		"start": "{{event.event_date}}",
-		"allDay":true,
+		"start": "{{start | date: "%Y-%m-%dT%H:%M:%S"}}",
+		"end": "{{end | date: "%Y-%m-%dT%H:%M:%S"}}",
+		"allDay": {% if start == end %}true{% else %}false{% endif %},
 		"url":"{{event.url}}"
 	}
 	{%unless forloop.last %},{%endunless%}