Richard Crooks's Website
Receiver Operator Characteristic Calculator
Use this form if your binary classifier produces qualitative results, eg. you are testing whether a type of stain which is meant to selectively colour cancer cells does so in a clinically useful manner that distinguishes patients with cancer from those without.
Use this form if you are measuring a marker and you want to see at what measurement you can be distinguish between positive and negative cases of what the marker is an indicator of. eg. At what measurement does a blood marker for cancer indicate that cancer is likely to be present.