Bitcoin Calculator tool allows you to convert any amount to and from bitcoin (up to six decimal places) and your preferred world currencies, with conversion rates based on the live CoinDesk Bitcoin Price Index. Non-USD BPI prices are implied based on rates obtained via openexchangerates.org. Firstly I will recommend Preev, 99bitcoins, Coinwarz, Cryptoground, and MyCryptoBuddy. They are relatively new and they support a variety of cryptocurrencies like Bitcoin, Ethereum, Bitcoin Cash and Litecoin. I find that it has a really nice UI and support.