Software/app for planning a run route

Hello,

Do any of you use software or an app for planning a route to run. I need to step up my training a gear to some longer distance runs and I want to be able to input 15-20k and it gives me a running route from home or work that will take me on a distance run of my choice rather than me me making it up as I'm going along.

Is there any people can recommend?

Thanks