A B O U T . Q U I E T S O F T™
QuietSoft™ provides XLL Add-ins for Microsoft^® Excel. Our products focus on mathematics, engineering, and astronomy. Check our products page for the latest information.

W H A T . I S . A N . X L L?
An XLL Add-in is a library containing compiled functions that are added to Microsoft^® Excel's built-in capability. When an XLL file is opened, the compiled functions it contains are automatically registered and their use is indistinguishable from that of any other Microsoft^® Excel built-in functions. Unlike VBA Add-in functions, there are no file links to maintain. You can move your XLL files anywhere on your local disk or network without worrying about re-linking the functions. XLL functions also have the advantage of being much faster than VBA functions because the XLL is compiled C code.

H O W . D O . I . U S E . A N . X L L?
Just like any other workbook or spreadsheet file, open the XLL file by double-clicking or using Microsoft^® Excel's File→Open command from the menu bar or ribbon. The functions are automatically loaded and you're ready to go. Alternatively, you can put the XLL file in your XLStart folder and it will automatically open when you start Excel.

W H A T . A R E . T H E . S Y S T E M . R E Q U I R E M E N T S?
Details can be found on our system requirements page.