Calculator Tab is a free online scientific calculator which works like your regular calculator. One feature that sets it appart from other calculators is that it's memory bank can store an unlimited amount of numbers and descriptions of these numbers for an indefinite length of time. The stored numbers can be sorted by date, by the number of uses or by name. Your saved numbers and their respective descriptions are saved directly on your computer, never entering the sphere of the internet, so that they are as secure as your workstation.

This calculator follows the standard order of operations. It can handle values from 4.9e-324 to 1.7e+308. To perform a calculation, press the calculator buttons with the mouse as you would write the symbols of the calculation. For example to calculate 2 + 5 * 8 press the buttons . To see the result (which in this case will be 42) and to terminate the calculation press the button. The exception to this approach is when using mathematical functions which only take one value: in these functions, the value always comes before the function. For more details see the section "Functions with one (x) value" below. To be able to use your keyboard instead of the mouse, you must first click anywhere on the calculator with the mouse.

Calculator Tab will not allow you to make ambiguous enteries and will tell you, what is not allowed if you try to make such an entry. If you, for example, try to enter the entry of will generate an error telling you, that you first need to enter a number before continuing with the calculation. The entry of will be ignored and you can continue with your calculation as though you had not entered it. This way you can always be sure about what exactly the calculator is doing.

- unlimited long-term memory storage
- pop-up version (for working with other documents)
- saving of settings between sessions
- highlighting of the last valid function
- possibility of switching between comma and point as decimal separators
- ambiguous input filter

There are two possibilities to store a value in the memory bank:

**1.** Using the button you can *quickly* store the displayed value in the memory bank. You don't need to enter a description.

**2.** Using the button you can store the displayed value in the memory bank and add your own description, which can be up to 64 characters long.

To open the memory bank press this button:

The memory bank will open and you will see your saved values. You can only see three values at a time. If you have more then tree values saved, you can use the scroll bar to the right of the saved values to scroll through the memory bank. To insert a saved value into the calculator, click on the value or the grey field surrounding it. To erase a value click on the button beside the corresponding value.

There are 2 possibilities to enter a negative number:

**1.** Press the button before pressing the number button. For example to calculate 2 + (-5) press the buttons .

**2.** Or press the button after the number button. For the same calculation as above press the buttons .

Making a *bracket negative* can only be accomplished using the first method, because the button can only change the sign of the last entered value. If you try to change the sign of a bracket using the button, you will get an error message.

Functions which take one value (, , , , , , , , , , , , , , ) are used in the following fashion: [value X] [Function], meaning that the value is always entered before the function. For example to enter sin(30) press the buttons .

Functions with two values (, , , , , , , , ) are used in the following fashion: [value X] [Function] [value Y]. For example to enter 53 (5 cubed) press the buttons .

Using the percentage buttons and , you can calculate either the percentage of a certain number, or what percentage of a certain number another number constitutes. The labels of the percentage buttons are meant as mnemonics. To calculate 5% of 50 (which is 2.5) enter . Here the mnemonic is clear: 5% (of) 50 is reflected in the label "x % y".

If on the other hand you want to know how many percent of 50 the value of 5 constitues, use the button . Here the mnemonic is: (How many) % (of) 50 (is) 5, which is reflected in the label "% y x". Keep in mind though, that the value of "x" comes before the value of "y" as explained above in the section "Functions with two (x and y) values". Accordingly, in order to calculate how many percent of 50 the value of 5 constitutes (which is 10%), enter .

To select your options for various settings, press the button. To turn to the next page of options press the button. To save your settings press the button. To cancel any changes you have made press the button.

You can select, whether a point or a comma should be used as a decimal separator.

You can select, how your saved values should be ordered: by date (most recent first); by most used (values used more frequently appear first); or by alphabet (values with descriptions first in the alphabet will appear first).

You can select, whether a short description of the fuctionality should appear, when you hover over a button. As you get more familiar with the calculator, you might not need this feature.

Once you have clicked inside the calculator, you can use your number buttons and fuction buttons like on any other calculator. Additionally, you then have the following shortcuts at your disposal:

Key | Function |
---|---|

[enter] | is equal to -or- enter/return |

= | is equal to |

[insert] | save a value without custom description |

i | save a value with custom description |

m | open/close memory bank |

o | options |

a | open/close left side functions |

s | open/close bottom side functions |

[backspace] | backspace button |

[delete] | reset button |

The "plus" button is used for adding two values or for specifying a positive exponent in scientific notation (note: since the default exponent is positive, it does not need to be explicitly specified).

The "minus" button is used for subtracting one value from an other, for entering a negative value or for specifying a negative exponent in scientific notation. For information about entering a negative value see the above section "Negative numbers".

RESTRICTIONS: None.

Addition on Wikipedia

Negative numbers on Wikipedia

The "multiplication" button is used for multiplying two values.

RESTRICTIONS: None.

The "division" button is used for dividing one value (dividend) by another (divisor).

RESTRICTIONS: The divisor must not equal zero. A zero in the divisor will generate an error and terminate the calculation.

The "square root" button is used for calculating the square root of a value. The square root of a value is the number, which multiplied by itself, gives the original value.

RESTRICTIONS: The value must be greater than or equal to zero. A value smaller than zero will generate an error and terminate the calculation.

The "root" button is used for calculating the root of a value. Although it is theoretically possible to calculate the root of a negative value if the root is an odd number, this calculator only calculates the roots of values which are greater than or equal to zero.

RESTRICTIONS: The value who's root you want to calculate must be greater than or equal to zero, except where the root is a number between -1 and 1 inclusive, which corresponds to raising the vaule to the reciprocal of the root. Otherwise a value smaller than zero will generate an error and terminate the calculation.

The "square" button is used for calculating the square of a value. The square of a value is the result of multiplying a value by itself.

RESTRICTIONS: None.

The "exponent" button is used for raising a value (base) to the power of another value (exponent).

RESTRICTIONS: Since raising a negative base to a power between -1 and 1 exclusive corresponds to the root reciprocal of the exponent, and trying to calculate a root of a negative number generates an error, this configuration will generate an error and terminate your calculation.

The "logarithm" button is used for calculating the logarithm to base 10 of a value. To calculate the logarithm of a value to a base other than 10 divide the logarithm of the value by the logarithm of the desired base.

RESTRICTIONS: The value must be greater than zero. A value less than or equal to zero will generate an error and terminate your calculation.

Logarithm on Wikipedia

Change of base on Wikipedia

The "natural logarithm" button is used for calculating the logarithm to base e of a value. To calculate the logarithm of a value to a base other than e divide the natural logarithm of the value by the natural logarithm of the desired base.

RESTRICTIONS: The value must be greater than zero. A value less than or equal to zero will generate an error and terminate your calculation.

Natural logarithm on Wikipedia

Change of base on Wikipedia

The "e" button is used for entering (an approximation of) the constant e into the calculator. e to the power of a value is the inverse of the natural logarithm of the same value.

RESTRICTIONS: None.

The "reciprocal" button is used for calculating the reciprocal of a value. The reciprocal of a value is 1 divided by the value.

RESTRICTIONS: The value must not equal zero. A value of zero will generate an error and terminate the calculation.

The "sine" button is used for calculating the sine of a value. For now, degrees are the only unit this function supports. It returns a number between -1 and 1 inclusive.

The "cosine" button is used for calculating the cosine of a value. For now, degrees are the only unit this function supports. It returns a number between -1 and 1 inclusive.

To convert degrees(deg) to radians(rad) and back, the following formulas can be used:

rad = deg * Pi / 180

deg = rad / Pi * 180

RESTRICTIONS: None.

Trigonometric function on Wikipedia

The "arcsine" button is used for calculating the arcsine of a value. Arcsine is the inverse function of sine. For now, degrees are the only unit this function supports. It returns a number between -90 and 90 inclusive.

RESTRICTIONS: The value must be a number between -1 and 1 inclusive.

The "arccosine" button is used for calculating the arccosine of a value. Arccosine is the inverse function of cosine. For now, degrees are the only unit this function supports. It returns a number between -90 and 90 inclusive.

To convert degrees(deg) to radians(rad) and back, the following formulas can be used:

rad = deg * Pi / 180

deg = rad / Pi * 180

RESTRICTIONS: The value must be a number between -1 and 1 inclusive.

Inverse trigonometric function on Wikipedia

The "tangent" button is used for calculating the tangent of a value. For now, degrees are the only unit this function supports.

RESTRICTIONS: None.

Trigonometric function on Wikipedia

The "arctangent" button is used for calculating the arctangent of a value. Arctangent is the inverse function of tangent. For now, degrees are the only unit this function supports. It returns a number between -90 and 90 inclusive.

To convert degrees(deg) to radians(rad) and back, the following formulas can be used:

rad = deg * Pi / 180

deg = rad / Pi * 180

RESTRICTIONS: None.

Inverse trigonometric function on Wikipedia

The "Pi" button is used for entering (an approximation of) the constant Pi into the calculator. Pi is for example useful in trigonometric functions and for calculating the circumference, area and volume of circular geometrical objects.

RESTRICTIONS: None.

The "modulo" button is used for calculating modulo of two values. Modulo is the remainder of one value (dividend) divided by another (divisor). The way it is implemented in this calculator, the result has always the same sign as the dividend.

RESTRICTIONS: The divisor must not equal zero. A zero in the divisor will generate an error and terminate the calculation.

The "scientific notation" button is used for entering values in scientific notation. A value written in scientific notation has the form: a x 10b. It is especially useful for entering very large or very small values. For example instead of entering 123000 you can enter 1.23e+5. And instead of entering 0.000123 you can enter 1.23e-4.

To enter a negative exponent press the minus (-) button after pressing the "scientific notation" button. When entering a positive exponent, you do not need to enter the plus (+) sign, because the exponent is positive by default.

RESTRICTIONS: Trying to place scientific notation in a point of an expression, where it cannot be placed, will generate an error message.

Scientific notation on Wikipedia

The "toggle positive / negative" button is used for switching the sign of the last entered number. The sign of a bracket cannot be switched. To make a bracket negative use the "minus" button before opening a bracket. For more information about negative vaules see the above section "Negative numbers".

RESTRICTIONS: None.

The "bracket" buttons are used for opening and closing brackets. Brackets are useful when the order of calculation should diverge from the standard order of operations. If for example in the expression 5 + 3 / 2 the term 5 + 3 should be evaluated first and then be divided by 2, then you it must be entered as (5 + 3) / 2.

Once a bracket has been opened, numbers will apear beside the bracket symbols on the bracket buttons, which indicate how many brackets have been opened or closed. The number beside the "close bracket" will be red as long as not all opened brackets have been closed. Opened brackets will be closed automatically upon evaluating the expression using the "is equal to" button. Once a bracket has been closed the output will be updated to reflect the value of the closed bracket.

The sign of a bracket cannot be switched. To make a bracket negative use the "minus" button before opening a bracket. For more information about negative vaules see the above section "Negative numbers".

RESTRICTIONS: Trying to open or close a bracket at a point of an expression, where a bracket cannot be placed, will generate an error message.

The "x percent of y" button is used for calculating a percentage of a value. For example to calculate 5% of 50 (which is 2.5), enter .

The "how many percent of y is x?" button is used for calculating how many percent one value of another value constitutes. For example to find out how many percent of 50 the value 5 constitutes (which is 10%), enter .

For more information about percentages see the above section "Percentages".

RESTRICTIONS: None.

The "ceiling" button is used for obtaining the ceiling of a value. The ceiling of a value is the smallest integer (whole number or negative) not less than the value. For example the ceiling of 4.2 is 5 and the ceiling of -4.2 is -4.

RESTRICTIONS: None.

The "floor" button is used for obtaining the floor of a value. The floor of a value is the highest integer (whole number or negative) less than or equal to the value. For example the floor of 4.2 is 4 and the floor of -4.2 is -5.

RESTRICTIONS: None.

The "decimal" button is used for obtaining the decimal part of a value. For example the decimal of 3.141 is 0.141.

RESTRICTIONS: None.

The "factorial" button is used for calculating the factorial of a value (for integer values) or for calculating (an aproximation of) the gamma function for the value + 1 for values greater than or equal to zero and non-integer values smaller than zero. The algorithm used for this operation is based on the "StieltjesLnFactorial" algorithm by Peter Luschny.

RESTRICTIONS: The value must be greater than or equal to zero, or non-integer smaller than zero. Integer values smaller than zero will generate an error and terminate the calculation.