Seriously? I have to open a conversion program just to figure out what temp to enter since I have to convert from fahrenheit to Celsius for it to even let me enter a temp. I would have expected something that simple even in a free app. It certainly was not worth the $2 I paid. Also there is no explanation of what the symbols and lines mean on the graph, no way to change the predicted fertile phase or ovulation date, and the website listed doesn't work.