diff --git a/src/lv_widgets/lv_calendar.c b/src/lv_widgets/lv_calendar.c
index 9aa6f3381..db44152f7 100644
--- a/src/lv_widgets/lv_calendar.c
+++ b/src/lv_widgets/lv_calendar.c
@@ -365,6 +365,27 @@ const char ** lv_calendar_get_month_names(const lv_obj_t * calendar)
     return ext->month_names;
 }
 
+/**
+ * Get the day of the week
+ * @param year a year
+ * @param month a  month (1..12)
+ * @param day a day (1..31)
+ * @return [0..6] which means [Sun..Sat] or [Mon..Sun] depending on LV_CALENDAR_WEEK_STARTS_MONDAY
+ */
+uint8_t lv_calendar_get_day_of_week(uint32_t year, uint32_t month, uint32_t day)
+{
+    uint32_t a = month < 3 ? 1 : 0;
+    uint32_t b = year - a;
+
+#if LV_CALENDAR_WEEK_STARTS_MONDAY
+    uint32_t day_of_week = (day + (31 * (month - 2 + 12 * a) / 12) + b + (b / 4) - (b / 100) + (b / 400) - 1) % 7;
+#else
+    uint32_t day_of_week = (day + (31 * (month - 2 + 12 * a) / 12) + b + (b / 4) - (b / 100) + (b / 400)) % 7;
+#endif
+
+    return day_of_week;
+}
+
 /*=====================
  * Other functions
  *====================*/
@@ -1067,25 +1088,4 @@ static uint8_t is_leap_year(uint32_t year)
     return (year % 4) || ((year % 100 == 0) && (year % 400)) ? 0 : 1;
 }
 
-/**
- * Get the day of the week
- * @param year a year
- * @param month a  month
- * @param day a day
- * @return [0..6] which means [Sun..Sat] or [Mon..Sun] depending on LV_CALENDAR_WEEK_STARTS_MONDAY
- */
-static uint8_t get_day_of_week(uint32_t year, uint32_t month, uint32_t day)
-{
-    uint32_t a = month < 3 ? 1 : 0;
-    uint32_t b = year - a;
-
-#if LV_CALENDAR_WEEK_STARTS_MONDAY
-    uint32_t day_of_week = (day + (31 * (month - 2 + 12 * a) / 12) + b + (b / 4) - (b / 100) + (b / 400) - 1) % 7;
-#else
-    uint32_t day_of_week = (day + (31 * (month - 2 + 12 * a) / 12) + b + (b / 4) - (b / 100) + (b / 400)) % 7;
-#endif
-
-    return day_of_week;
-}
-
 #endif
diff --git a/src/lv_widgets/lv_calendar.h b/src/lv_widgets/lv_calendar.h
index 1e0f88cdc..66f2b24ca 100644
--- a/src/lv_widgets/lv_calendar.h
+++ b/src/lv_widgets/lv_calendar.h
@@ -182,6 +182,15 @@ const char ** lv_calendar_get_day_names(const lv_obj_t * calendar);
  */
 const char ** lv_calendar_get_month_names(const lv_obj_t * calendar);
 
+/**
+ * Get the day of the week
+ * @param year a year
+ * @param month a  month (1..12)
+ * @param day a day (1..31)
+ * @return [0..6] which means [Sun..Sat] or [Mon..Sun] depending on LV_CALENDAR_WEEK_STARTS_MONDAY
+ */
+uint8_t lv_calendar_get_day_of_week(uint32_t year, uint32_t month, uint32_t day);
+
 /*=====================
  * Other functions
  *====================*/