Does my iphone need a new battery?

It turn off itself even with 60% or30% battery. It won't turn on until it comes up with the battery icon then i charge it then i works. Is it worth buying a new battery for it? I have had it since 2009. Its an iPhone 3gs 8gb.

Probably not battery issue but it may be too! This can also caused by software problem.did you tried restoring your phone through itunes and see whether it helps?

Since you have had that 3-4 years now, I wouldn't mess with it, just get iphone 4 free with a 2 year contract and that way you get an upgrade free.