Question: When does a person leave i’tikaaf, is it after sunset on the night prior to `Eed or after Fajr on the day of `Eed?
Response: The person in i’tikaaf leaves i’tikaaf once Ramadhaan finishes and it finishes as the sun sets the night prior to `Eed. He enters i’tikaaf at sunset (prior) to the 20th day of Ramadhaan. This is so as the last ten (nights) of Ramadhaan start from sunset of the night (prior) to the 20th day of Ramadhaan and ends at sunset of the night (prior) to `Eed.
Shaykh Ibn ‘Uthaymeen
Fataawa Ramadhaan – Volume 2, Page 872, Fatwa No.859;
Fataawa ash-Shaykh Muhammad as-Saalih al-‘Uthaymeen – Volume1, Page 551.Fatwaonline.com