The flight time from Bali to Ha Noi, Viet Nam is about 4 hours, 15 minutes.
For direct flights, about 9.75 hours flying time.
For direct flights, about 15.5 hours flying time.
The flight time from Manchester, United Kingdom to Bali is about 15 hours, 36 minutes.
3 hours
the flight time from jakarta to Bali and from Bali from Jakarta is 1 hour and 30 minutes. but, it is not an exact time. for example: you left Jakarta or Bali at12:30 p.m but sometimes you arrived at Bali or Jakarta at 02:01. so, the pilots will try to make there on time.
flying from Barcelona ot Singapur and then to Hanoi
Singapore time is UTC+8 and Hanoi time is UTC+7, therefore, when it is 11am in Singapore, it will be 10am in Hanoi.
Bali is in the Indonesia Central Time Zone (WITA), which is 8 hours ahead of Coordinated Universal Time (UTC+8). Bali does not observe Daylight Saving Time.
The time difference between London, UK and Hanoi, Vietnam is 6 hours. Hanoi is 6 hours ahead of London. So, when it is 3 am in Hanoi, it is 9 pm in London.
Any side
the best time to visit Bali is April and October .
Delta airlines claims about 52 hours, which I think is too much, You should check your local airlines' website.