You can visit on above mention timings mentioned by Rahul but I personally love to visit at sunset time.
The Taj Mahal is the most iconic symbol of love in the world. People across the globe come to see this ivory-white marble beauty. The Mughal emperor, Shah Jahan built this magnificent beauty in the memory of his late beloved wife Mumtaz Mahal as a tribute to her.
UNESCO declared the Taj Mahal a world heritage site in 1983 and it attracts around 7-8 million visitors annually. It is one of the Seven Wonders of the World and regarded as the best example of India’s rich history.
The Taj Mahal is open 30 minutes before sunrise and closed 30 minutes before sunset every day except Friday. One can visit the Taj Mahal from 6:00 am in the morning to six thirty in the evening.
Taj Mahal is closed for general viewing on Fridays. It is open on Friday afternoon for those who want to attend prayer at the Mosque inside the Taj Mahal. There is no limit how long a tourist wants to stay inside the monumental complex during the operating hours.