# Units

The calculator has in-built units conversions and constants. Using conventional calculators and reference books it is often difficult to find a conversion factor between the pair of units you are dealing with and you are forced to convert in several error prone steps. This problem is eliminated with the units conversion facility. The conversion function also eliminates the risk of confusion about 'which way' to use a factor that arises when converting between different units systems of dimensionally complex quantities.

## Example using units conversion

Suppose you have a value for a property, dynamic viscosity say, quoted in non-SI units, and the formula you are computing is in SI. First, enter the value into the calculator display. Next, click the unit button and select the property dynamic viscosity from the Properties box.

Then in the From box select the set of units in which the value has been entered (e.g. slug/ft-sec). Now select the desired units in the To box. If the desired units are SI, you can just click the SI button, rather than searching for them in the drop down edit box. Finally click the OK button (or return on the keyboard) and the converted value will be shown in the calculator display.

You can click the Cancel button to return to the calculator without performing any conversion.

Now that the conversion has been set up, you can use the same conversion on another value using the cnv> button. Any value can now be instantly converted from slug/ft.s to kg/m.s using this button. To convert back from kg/m.s to slug/ft.s use the shift button which changes the "cnv>" button to "<cnv", which does the reverse conversion.

You can use the Find button to search for a property or units from the properties database.
To modify the properties database press the Edit button next to the properties or units.

## Currency Conversions

Currency conversions are supplied to convert between the Euro and those European currencies that have fixed conversion rates, i.e. those where the Euro is adopted. Some European countries have retained their own currency, either because they are not in the European Union, or because they have chosen to retain their currency (e.g. Great Britain). Therefore these currencies, along with non-European currencies, have spot conversion rates which can be expected to change over time. Updated conversion rates will be posted to the calculator.org website periodically.

Obviously currency is outside the scope of the SI units system. The "SI" unit for currency is the Euro, which simply means it is the default currency.