Flight Haneda Airport departs from Tokyo Haneda Airport at 10:55 and arrives at Singapore Changi Airport at 17:15.
The flighttime is about 7h 20m. The distance travelled ("as the bird flies"): 4314 Km. So the average speed is roughly 588 Km.
There is an 1 hour time difference between Tokyo and Singapore
The best day to arrive at Tokyo is Thursday and it would be best to avoid Friday, as prices are on average 47.16% higher than on Thursday. (Average prices, based on 407749 datapoints.)
We have a lot more statistics for flights NH 841 and between Tokyo and Singapore.