Type in any conversion, and Convertr will try to guess what you're looking for. Start with something as simple as "4km to miles".
Convertr © Richard Ye, Nick Frosst 2011. All Rights Reserved.
Unit information from WolframAlpha
Disclaimer: Though every effort has been made to verify the accuracy of the results, inaccuracies due to calculation or numerical error could still result. Use this application at your own risk.