Joey, they have one built in on their site. On the main page, otherwise called the Dashboard page, their is a blue button that says lend Bitconnect. Click that button and a pop up window comes up.... there it says something about "volatility software interest," click that link and it takes you to a page where it shows you the daily interest rate and other data. There is a calculator there you can use.

Just for your information, Bitconnect will be going down for a few days due to the Bitcoin Segwit stuff, so for a few days there will not be a trading/interest payments when this does happen. I have advised for some to wait until after this to see what happens. The more adventurous and daring ones still went for it, others are waiting. Let me know if you have any other questions @joeyknowsbest