Just a simple Unity scene with SteamVR 1.0.8 dropped in. The floor is a compass with posts at every 10* and there is an additional ring of posts every 10* along the YZ axis. Open in Unity 5.3+ and run.
Stand in the middle, look forward and count the posts to determine your effective FOV.
Trying to look directly at the edges will show you how much the FOV changes as opposed to when you are looking straight forward and see the edges in your periphery.