Yes, the router should tell you.
Using the network and sharing Status/Details page is not going to show you the speed. When you are plugged it it will show you at 100mbps because you are running through a network cable and that's the link speed.
You need to check your router status pages for info.
I'm only getting 165mbps with 75-85% signal strength. I'm also 2 floors down from my router.