High precision calculator with unit and radix converters.
http://www.haxial.com/products/calculator/
Award/review service for other math web sites and web pages, with a new selection each week.
http://www.cms.math.ca/Kabol/knotlinks.html
Online calculator, written in Java. Includes Square root button and number memory. Source code can be downloaded.
http://www.df.lth.se/~mikaelb/pocketcalc-enu.shtml
Dave Rusin's survey of research-level mathematics, with introductory articles for non-mathematicians and hyperlinked bibliographies in each of dozens of research areas.
http://www.math.niu.edu/~rusin/known-math/
Variable-precision floating decimal calculator programmes by Harry Smith.
http://pw1.netcom.com/~hjsmith/Calc.html
A JavaScript Calculator that adds, subtracts and multiplies fairly large numbers. Functions are added in my copious free time.
http://www.petting-zoo.org/Calculator.html
Replacement for the standard Windows calculator with many additional features.
http://www.rayslab.com/calculator/
Fully functional expression calculator. Linux/Windows versions. Free trial download.
http://shareit1.element5.com/programs.html?productid=186383