Help needed for getting the data transfer speed

Hi All,

I am trying to get the data transfer speed between two host in a LAN.
so what I am doing is,
using RTT value(UDP over) for calculating it. The packet size I am
taking is equal to the MTU of the path between them(i.e. 1500 bytes),
to avoid fragmentation and reassembly cost. But using that I am
getting the 37 Mbps speed, is it OK. Though if I increases the packet
size in RTT calculation this value also increases.
So what packet size I should take or whether I am doing in right
direction or not??

Otherwise can any one suggest any other method.

I am using a LAN with speed 100 Mbps.

Rajat.