Free online scientific calculator software for windows

A general-purpose scientific calculator that you can use as a computer-desktop calculator Java Scientific Calculator is a small, simple and easy-to-use Java-based application that represents a general-purpose scientific calculator which you can use as a computer-desktop calculator or in a web application.
In addition to basic arithmetic functions it provides trigonometric functions, logarithms, powers and roots, complex numbers, binary, octal, decimal and hexadecimal calculations, logic, scientific notation, memory, statistical funcions (mean, and population and sample standard deviations), permutations and combinations.
Java Scientific Calculator also supports editing and replay of input and copying of output to the (system) clipboard. You can resize the application to one of three sizes and use the keyboard instead of the mouse for all keys.
Java Scientific Calculator was originally designed as part of a web application to show how you can use a calculator to calculate confidence intervals. This is why it has statistical functions and behaves in a similar way to pocket scientific calculators.
System requirements:
- Java 2 1.5

The Scientific Calculator Opera Widget supports trigonometry, logarithms, combinations and permutations and more The Scientific Calculator Opera Widget is a two-line scientific calculator that provides the look and feel of a real calculator.
With a dedicated line for the equation and another for the result, complex equations can be written with ease.
You can input numbers and simple functions via the keyboard and more advanced functions are available using the normal calculator buttons.
Main features:
- Trigonometry
- Logarithms
- Combinations and permutations
- 7 programmable memory locations
- Pseudo-random number generator
If you dont like the default look, you can change it! Five different skins are provided.
Note: This calculator is only as accurate as the JavaScript runtime environment, floating point rounding errors can occur.
System requirements:
- Opera 9 or later

Scientific and Business RPN Calculator with :
- mouse operated, with mouse "keypad"
- standard functions
- trigonometric functions
- finance functions
- RPN (Reverse Polish Notation) mode
- infinite and circular stack
- registers display (stack, 11 memory regs, finance registers)
- display intermediate keystroke and results, status bar
- navigation through history for entry correction and replay (with operation delete, skip, ... options)
- save and reload your calculations to file
- multiple auto-save on exit options
- print
- quick help
- ...
... unmatched features free for ever (no trial period, full version for free)!