calculators

 Here is a list of online calculators that you may find useful.  All of these calculators are free.

7  Stones
Online scientific and statistical calculator.

Calcoolate
The coolest calculator on the web.

Desmos
Desmos is a free online graphic  calculator.

CalcResult
Calculator for every formula, with unit  conversion and printable calculation history built in. 

eCalc
Both a basic and scientific mode calculator, it includes advanced features like unit conversion, constants and equation solving.

gCalc
Designed to provide a basic, easy-to-use set of  graphing functionality for algebra, pre-calculus, calculus and  more...

Screen Calculator
This is the biggest calculator I have  seen!  

web2.0Calc
Online calculator with the potential to share  calculations.

Calculators - Online Centre
Over 18,400 online  calculators.

Calculator Tools and Apps
This is a  comprehensive lost of tools and Apps for calculating.