diff --git a/src/gcal-window.c b/src/gcal-window.c
index 8548f069..d4ed8df9 100644
--- a/src/gcal-window.c
+++ b/src/gcal-window.c
@@ -414,8 +414,12 @@ update_active_date (GcalWindow   *window,
       !g_date_valid (&old_week) ||
       g_date_get_iso8601_week_of_year (&old_week) != g_date_get_iso8601_week_of_year (&new_week))
     {
+      gint offset;
+
+      offset = g_date_time_get_day_of_week (date_start) % 7 + get_first_weekday ();
+
       date_start = g_date_time_new_local (new_date->year, new_date->month, new_date->day, 0, 0, 0);
-      date_start = g_date_time_add_days (date_start, (get_first_weekday () - g_date_time_get_day_of_week (date_start) + 7) % 7 - 7);
+      date_start = g_date_time_add_days (date_start, offset);
       range_start = g_date_time_to_unix (date_start);
 
       date_end = g_date_time_add_days (date_start, 7);