Flight Narita International Airport departs from Tokyo Narita International Airport at 18:15 and arrives at Singapore Changi Airport at 00:35.
The flighttime is about 7h 20m. The distance travelled ("as the bird flies"): 4385 Km. So the average speed is roughly 598 Km.
There is an 1 hour time difference between Tokyo and Singapore
The best day to arrive at Tokyo is Sunday and it would be best to avoid Saturday, as prices are on average 161.04% higher than on Sunday. (Average prices, based on 204066 datapoints.)
We have a lot more statistics for flights NH 801 and between Tokyo and Singapore.