Calculator 2.0 Instructions To calculator page

This is a free online math/scientific calculator similar to those from TI, Casio, HP and others. It supports functions for algebra and trigonometry.

Enter a formula either by typing on the keyboard (see keyboard input below), pressing the buttons on the calculator with the mouse, or a mixture of both. Type in the formula as you would say it, then press = or the keyboard enter key. For example:

Find the value of the equation:   by pressing the calculator buttons:
3 x2 + 4 x2 ) =
The display will show:   sqrt(3^2+4^2) = 5

Or type it in on the keyboard using the full function names (see below)
s q r t ( 3 ^ 2 + 4 ^ 2 ) enter


Functions can be entered by

  • pressing the function button on the screen with the mouse, for example: sin
  • type it in on the keyboard, for example: s i n (.

The table below shows what to type for each function. The function has an argument which must be in parentheses, for example tan(12). When you enter a function from the screen buttons, the first parenthesis is entered for you. For example when you press the cos button, it enters "cos ("

Function Button Typed in Description
sin(x) The trigonometry sine function*.
See Trigonometry Overview
cos(x) The trigonometry cosine function*.
See Trigonometry Overview
tan(x) The trigonometry tangent function*.
See Trigonometry Overview
Arc Sine
asin(x) The trigonometry inverse sine function*. The angle whose sine is x. See Trigonometry Overview
Arc Cosine
acos(x) The trigonometry inverse cosine function*. The angle whose cosine is x. See Trigonometry Overview
Arc Tangent
atan(x) The trigonometry inverse tangent function*. The angle whose tangent is x. See Trigonometry Overview
Square root
sqrt(x) Square root of x.
log(x) The log base 10 of x. The power to which you must raise the base (10) to get x.
Ten to the power x
pow(10,x) Ten raised to the power x.
x squared
x^2 x raised to the power 2.
Natural Log
ln(x) The log base e of x. The power to which you must raise the base (e - approximately 2.718) to get x.
exp(x) e (approx 2.718) raised to the power of x.

The following functions have no buttons on the calculator. They can be entered by typing them on the keyboard only.
Min   min(a,b) Returns a or b whichever is smallest.
Max   max(a,b) Returns a or b whichever is largest.
Abs   abs(x) Returns the absolute value of x (always positive)
Pow   pow(x,y) Returns x raised to the power y. pow(2,3) = 8
Round   round(x) Returns x rounded off to the nearest whole number
floor   floor(x) Returns the highest integer less than or equal to x
ceil   floor(x) Returns the smallest integer greater than or equal to x

* Note: The six trigonometry functions will operate in degrees or radians depending on the setting of the control located just below the display window.

Tan() special note: If you calculate tan(pi/2) it should be an error since the tan of a right angle is undefined. However, pi in a computer is an approximation, with the result that tan(pi/2) calculates to a very large number instead.

If the calculator is in degrees mode, then tan(90), tan(270) etc will in fact produce an error, since they are undefined.

Arithmetic Operators

Once you press the '=' button or press 'Enter', the expression is evaluated according to normal algebraic operator precedence. That is, parentheses first, followed by exponentiation, multiply, divide, add and subtract. (PEMDAS)

Function Button Typed in


The three constants keys enter the values at high precision (even if only 3 digits are displayed). From the top:
  • Pi - approximately 3.142.. See PI definition for more.
  • e - approximately 2.718..
  • Square root of 2. - Approximately 1.414..

Scientific notation

Scientific notation (E.G. 1e+3 for 1000) is not supported.


There are four memory locations you can use to store temporary results, named A,B,C and D. Under each is a button labeled 'set'. When you press 'set' the current result is copied into that memory. When a memory contains a value, there is a dark border around the memory button. If you hover the mouse over the button it will show the current value stored in it.

Pressing "CLR" also clears the memory locations.

To use the contents of a memory in a calculation, simply click on the corresponding memory button and its value will be entered into the calculation. On the keyboard enter the letter a,b,c or d. It is not case sensitive. Using a memory that has nothing in it results in an error.

The ANS button

Pressing the ans button inserts the result from the previous line into the formula. If entering this from the keyboard, enter the three letters: a n s.    Not valid on the first entry.

Decimal places displayed

Using this control, you can select how many significant digits are displayed in the results. This only controls the display. Internally, all calculations are performed and stored using the maximum possible precision. For example, with three digits displayed, enter 1 0 ÷ 3 = to see the result 3.333. Then press × 3 = and you will see that the result is 10, not 9.999.

It controls the number of significant digits after the point. For example, if the result was 1.002782, and you displayed 3 digits you get 3 digits after the zeros after the point, or 1.00278. Trailing zeros are never displayed.

Automatic Features

Automatic multiplication

If a function (such as sin() ) is preceded by a number, the calculator assumes you want to multiply them. For example 3cos(2.1) will be automatically treated as if you entered 3*cos(2.1): three times the cosine of 2.1

Note: This feature can mislead you. For example if you enter 1/2sin(.5) the calculator inserts a multiply between the 2 and the sin. Since there are no parentheses, the calculator executes it from left to right so it operates as though you meant (1/2)sin(.5).

Automatic chaining If the first thing you enter on a line is multiply, divide, add, subtract or exponent, it assumes you want to work on the the result from the previous line. For example, if you enter 1 + 1 = and get the answer 2. Then enter + 3 =. It will add the 3 to the previous answer and get 5.
Automatic parenthesis balancing When you press = or enter, it will automatically add enough closing parentheses to balance them. For example, if you enter ( 4 + 6 = it will add an extra closing parenthesis and get the answer 10. Note: This may not always produce the desired result. It is best to always enter the correct expression yourself.
Function chaining If the last thing on a line is a function with no argument, then it assumes you want the previous result to used as the argument. For example, enter
2 + 6 = and get the answer 8. Then enter sin =. It will find the sine of 8, the previous result.

Unary minus

If the first character is a minus, the calculator will assume you want to subtract from the previous result. If you want the first number to be negative, you can either:
  • Enter a zero first. For example to enter -6+2 enter 0-6+2 instead.
  • Put the number in parentheses.. For example (-6)+2 or (-6+2).

Full Screen mode

Click on the button to enlarge the calculator. A new window will open as large as your monitor will allow, containing a new instance of the calculator. Press "close" or close the large window in the usual way when you are done with it. This feature is useful when using a projector.

Keyboard input

The keyboard can be used for entry at the same time as the buttons on the calculator. The numbers and operators on the numeric keypad to the right of the keyboard can also be used. However, due to a problem with most browsers other than Internet Explorer, you must first click anywhere on the calculator to allow it to receive input from the keyboard.


This does not support RPN (Reverse Polish Notation) used by many HP calculators. It uses the algebraic style used on calculators from such companies as Casio and TI.


The expression parser in this applet was developed by Douglas Ensley and Barbara Kaskosz.