Depends what type you get. My granddad had one that had two recline positions so not much room needed. Then he replaced it with a new one that almost went flat.
I've just bought a recliner chair. I've found that about an inch and a half allows it to fully, recline. It moves forward within itself as it goes back. If you see what I mean.
We've been toying with having one and have sat on a few in showrooms. My memory suggests you don't need any extra room behind, you can have them up against a wall - it's in front you need, they all move forwards.
They are all over the place, bednobs. DFS, SCS, etc etc. I got mine from the British Heart Foundation charity. Brand new and half the price of the ones, in the shops.