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General Information, Facts & Tables
[Using G.I.F.T. Calculators]

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There are literally hundreds of calculators on this site, and several tools have been provided to assist with their navigation and usage.

Each calculator page is divided into three sections, "Formula", "Units" and "Calculator" as described below. Where a calculation requires multiple formulae to be combined, click on the "open another" link at the bottom of the "Overview" section to open another copy of the same calculator in a new Browser window, and any common values can be copied from the result of one page, and pasted into the variable entry box of another page using either the operating system Clipboard.(In MS Windows use the "Ctrl +C" keyboard shortcut to copy, and the "Ctrl + V" keyboard shortcut to paste.)

There will be times where the required information will require a combination of more than one calculation / data page, and the "Cookie Clipboard" allows for the storage of up to 10 values. This functionality requires that your Browser has "Cookies" enabled. Another benefit of this clipboard is that the values are saved locally, so that they will be available when you return to this site.

Note! All of the calculator pages within this site are written in Javascript, and require that this functionality is enabled in your Browser.

Note! Calculator Under Construction. (Updating text to explain additional functions)


Data Entry Controls

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The table below lists the types of control used to accept user input with a brief explanation of their usage.
Note! Some controls are marked as "Read Only", and will not accept input. These controls are displayed differently. Even if a control is "Read Only", its contents can still be copied to the "Cookie Clipboard", or the "MS Windows Clipboard".

Used to initiate an action such as perform a calculation.


Single Line Edit Controls:
These controls accept a single line of text (alphanumeric or symbols) and are set as "read only" when they will not accept input. In the sample controls at right, the upper control (dotted border) will accept input, and the lower control (solid border) is "read only".


Multiple line Edit Controls (Memo):
Used where multiple lines of text are to be displayed, or required to perform a ca:


Combo Boxes (Drop Down Lists)
These controls are used to select a value from a predetermined list.


Check Boxes
These controls are used to set / unset an option. :

Check Box

Option Buttons (Radio Buttons)
These controls are used to select only one option from the group.

Option #1
Option #2


Cookie Clipboard

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In order to exchange values between pages, the "Calculator", "Unit Conversion", and some "Tables" have links to a "Cookie Clipboard" which stores up to 10 values. These values use the "cookies" function of your Browser, and they are stored even between sessions (for up to one year). As a new value is added, all other values will be moved down one place with the last value being deleted. so that data can easily be exchanged between the controls on their pages without the need for re-typing. This Clipboard also stores the last ten values so that they will be available when you return to the G.I.F.T. web site.
It uses cookies, which are small text files stored on your computer, therefore if you have cookies disabled on your Browser, the Cookie Clipboard will not function.

Displays the "Cookie Clipboard" in a new window. Note! If it is already open, the contents will be refreshed.

Copies the value in the adjacent control to the "Cookie Clipboard".

Pastes the last entry from the Cookie Clipboard into the adjacent control.

See Also: Cookie Clipboard Overview (In depth explanations)


Colour Coding

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To assist readability, the individual components of the formula are colour coded. This helps to distinguish between characters that could be misinterpreted such as l (lower case "L"), 1 (numeral one), and / (forward slash). eg l = 1 / 100.
All formulae and variables use the font "Times New Roman" which has "ornaments" at the end of each line of  the character which makes it easier to distinguish between characters.
Variable names are in blue italic, eg A, a, l
Numeric values are in red, eg 23, 100, 1
Operators are in green, eg +, -, /


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Because the calculators use Javascript which is handled by the Browser, the accuracy is dependant on how it is implemented within the Browser. When using variables with large differences in magnitude between them (eg a = 1 000 000 000, b = 0.000 000 001, c = a/ b, the result will be less accurate as the magnitude between them increases.
None of the calculators round down values (unless explicitly noted).


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Some of the expressions may contain additional "seemingly unnecessary" brackets, however they are there to improve their readability, or to isolate related components. View the page on Numeric Order of Operation for information on reducing formula for entry in a hand held calculators.

Formula sections contains the formula used to calculate the unknown variable(s), and are in one of two formats, "Simple" and "Compound".

Simple Formula:
Where there are only three variables the formula will be presented as a simple list with the required variable on the left of the equals sign, and the formula to calculate that variable on the right of the equals sign.

a = b * c
b = a / c
c = a / b

Compound Formula:

Some calculations have multiple variables which are related to the same value. eg radius = diameter / 2. Where this is the case the variables are arranged in a table, with the formula for the required value (left column) listed under the cell containing the known values.

These calculators have a table of

examples: AC Ohms Law Calculator, Trigonometric Formula Calculator.



1 & 2

1 & 3

2 & 3
















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The combo box at the left of the calculator allow the variable measurement to be entered (and converted to) different units. variables in the formula can be

The measurement units listed in the combo box are in order of their magnitude from smallest (top of list) to largest (bottom of list). eg millimetre appears above metre, which appears above kilometres.
Where a measurement unit has a defined symbol it will be enclosed in brackets immediately after the unit name. Some units have additional text to differentiate it from similar units, which is enclosed in square brackets. eg "pint (pt) [UK]", "pint (pt) [US]".

The units displayed in the combo boxes are limited to commonly used imperial and metric units. If additional conversions are required, the value can be copied to the "Cookie Clipboard" and pasted into the appropriate converter.

a = a
b = b
c = c



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Where all variables are required to solve the formula, (except the unknown) they have the "Calculate" buttons beside the variable entry controls. Once these variables have been entered, press the "Calculate" button immediately to the right of the variable required.

The buttons will display the prefix "Calc by" when the other unknown values are to be calculated from a given value, and "Solve by" when the other values will be used to calculate the value.

unit []:



unit [symbol]:




 Metabolic Rates


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