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Unit Conversions and Constants

If you have purchased RealCalc Plus, you can customize the unit conversion and constant tables. These are stored in an xml data file, which can be exported to the SD card, edited, then imported back into the calculator.

To customize the conversions/constants:

  1. Go to Menu > Settings > Customization Options.
  2. Select 'Export ...'. The data will be written to your device's storage in 'realcalc/data.xml'.
  3. Copy the data.xml file to your computer.
  4. Edit the data.xml file, following the existing data as an example. You can add, change or remove units and constants or whole groups. You will need to use a text editor which supports UTF-8, such as Notepad on Windows (but not WordPad). A more powerful editor such as Notepad++ is recommended.
  5. When finished, copy the file back to the same place on your device.
  6. Select 'Import ...' from the Customization Options screen. If there are any errors in your xml file, you will be notified and the import will not change anything. Correct the errors and repeat the import.
  7. Return to the main calculator screen. The CONV and CNST functions will now use your new custom conversions and constants.
  8. It is recommended that you keep your data.xml file as a backup. If you have to uninstall RealCalc for any reason, your customizations will be lost, but you can re-import the data.xml file at any time.

To restore the default conversions/constants:

  1. Go to Menu > Settings and select 'Customization Options'.
  2. Select 'Reset to defaults...' and confirm.
  3. Return to the main calculator screen. The default CONV and CNST functions will now be restored.


Fuel Consumption

Showing use of inverse units. In this example, the ratio for litres per 100km is set as if the unit were 100km per litre, and the attribute inverse="true" is added.

  <group name="Fuel Consumption">
    <unit name="Kilometres per litre"   symbol="km/l"        ratio="1.0"                    />
    <unit name="Litres per 100km"       symbol="l/100km"     ratio="100.0" inverse="true"   />
    <unit name="Miles per gallon (Imp)" symbol="mpg (Imp)"   ratio="1.609344/4.54609"       />
    <unit name="Miles per gallon (US)"  symbol="mpg (US)"    ratio="1.609344/3.785411784"   />


<group name="Frequency/Wavelength">
  <unit name="Hertz"     symbol="Hz"  ratio="1.0"              />
  <unit name="Kilohertz" symbol="kHz" ratio="1000.0"           />
  <unit name="Megahertz" symbol="MHz" ratio="1000000.0"        />
  <unit name="Metres"    symbol="m"   ratio="299792458"        inverse="true" />
  <unit name="Feet"      symbol="ft"  ratio="299792458/0.3048" inverse="true" />