Slow internet speed

My service says that i should get download speeds of up to 100 mbps.   But, when I check it on different laptop and desktops it is only running a download of around 27 mbps max.  This is with only one device access to wifi at the time.  Is there a way for the service to be checked leading to the residence to eliminate where the problem is before the residence or in home wiring, etc. Modem was reset, but it did not effect.  Using newer netgear modem and Airport Expreme.