The standard calculator is a general tool for performing basic arithmetical calculations.

The calculator allows a calculation to be built up by via calculator buttons, keyboard entry and pasting text. The mode in which the calculator is operating influences when the calculation is performed. There are currently two modes of operation (manual and automatic calculation) and the toggle button Switch Auto-Calculation On/Off is used to move between them (with the default mode being manual calculation). In both cases a calculation is peformed when = is pressed or typed, or Enter is chosen. However, in automatic calculation mode, a calculation is also triggered when a button representing a unary operator/function, such as sqrt, is pressed. So whether this is required or not should determine which mode is chosen for the calculator.

The calculator stores the last ten calculations performed on it in its history. Three of these historical calculations are viewable at any one time, but the ones shown can be changed by scrolling through the history using the up and down arrows to the right of the calculator display. In addition, the result of any valid historical calculation can be readily used in a new calculation by clicking on the Use button for that calculation.

The calculator buttons are present both for forming the calculation and also as a guide to the allowed characters and operators/functions. However, if JavaScript is disabled, the buttons are also disabled and are thus not useable for entering calculation text.

The calculator supports the operators/functions given in the list below...

- The basic binary arithmetic operators: addition(+), subtraction (-), multiplication (*) and division (/).
- The negation operator (-), which can also be applied or removed from the whole calculation text by using the +/- button.
- The percentage operator (%), which forms a percentage value together with the operand to its left.
- The 1/x calculator button, which is used to obtain the multiplicative inverse of part, or the whole, of the calculator text, depending on the calculator mode of operation.
- The square root function (sqrt).

Associated tool link: http://www.coggit.com/tools/standard_calculator.html