Flight Narita International Airport departs from Tokyo Narita International Airport at 08:20 and arrives at Singapore Changi Airport at 14:35.
The flighttime is about 7h 15m. The distance travelled ("as the bird flies"): 4385 Km. So the average speed is roughly 605 Km.
There is an 1 hour time difference between Tokyo and Singapore
The best day to arrive at Tokyo is Wednesday and it would be best to avoid Friday, as prices are on average 568.83% higher than on Wednesday. (Average prices, based on 417123 datapoints.)
We have a lot more statistics for flights SQ 8643 and between Tokyo and Singapore.