@hskoglund this did indeed work. and the results are correct:
"2025/01/04"
Thank you for your help.
Here is the code if anyone is curious:
void jalaliToGregorian(int year, int month, int day) { QCalendar calendar(QCalendar::System::Jalali); QDate gregorianDate = calendar.dateFromParts(year, month, day); qDebug() << QString("%1/%2/%3") .arg(gregorianDate.year(), 4, 10, QChar('0')) .arg(gregorianDate.month(), 2, 10, QChar('0')) .arg(gregorianDate.day(), 2, 10, QChar('0')); }