Support user defined functions and variables, absolutes, logarithms with any base, factorials and much more. Of course the usual trig functions are available such as sin, cos, tan, asin, acos, and atan. Reports capabilities and simply the best unit convertion someone expects. This calculator's source can be copied and saved to the desktop for complete customization. You can edit the page by removing anything you don't want and resize the text area to have plenty of space. Be sure to try the examples from the pull down menu at the site.