how to work out uv filter needed?

[dark_angel]

I've just brought a nikon d3000 dslr camera with a 18-55mm lens. I'm looking at getting a uv filter but not sure on how to work out size needed. They are listed in 18, 17, 52, 54, 55 sizes on websites etc but mine is 18-55mm so what do i go for?
Thanks

 

[Justin]

get the 52mm. 52mm is your lens diameter.

 

[dark_angel]

ah thanks heaps.