I put together a Lens Focal Length Equivalency Calculator which is basically a handy chart to see what any focal length lens is equivalent to on a variety of common film/sensor types. I also put in a custom film size field so you can calculate for any type of camera I haven’t included.

I’m planning on adding photos with crop lines for common focal lengths as well to add a visual element to the chart, however I haven’t yet shot the necessary photos for that.

Please tell me if you notice any error with my maths!
Tiny link: http://taii.cc/2q