CC: JLA

Agree, digitalifelesss
For me, I would choose to run either NPerf or Cloudfare test.
Both give a very thorough test, and unlike Speedtest which gives the last "end" result,
meaning if it ends at 1Mbps instead of earlier on it goes up to 10MBPs for 1 second, the end result will be 1Mbps.

Both of this website gives an "average" speed. This is real world.
The only thing is : You need to wait longer for these tests.

I only use Speedtest for quick diagnostic (which sometimes I will terminate halfway), and not to serve as actual speed.