At Aqua-Calc.com, use the Volume table listed on the drop-down menu beneath the Tables tab on the main page, selecting Imperial gallons as the unit to convert from and selecting the desired unit to convert to, such as dekaliter, Imperial pint or U.S. gallon. On the displayed chart, modify the range of measurements by typing a number for the start of the range in the From box and then selecting an increment on the By drop-down menu.
ConvertUnits.com features an online calculator that converts Imperial gallons to other units of volume. Type "Imperial gallons" in the Convert box on the main page, and then type a unit to convert to, such as "pints" or "liters," in the To box. Click the Go button, type the quantity of Imperial gallons to convert in the Imperial Gallons box, and then click the Convert button to display the converted quantity in the unit desired.
Many mobile device apps convert volumes from one unit to another, such as Mila's Liquid Volume Converter for iPhone and iPad and ZanteSoft's Volume Converter Free for Android, both available at Appcrawlr.com. CheckYourMath.com features a tutorial on how to convert Imperial gallons to other units manually and includes formulas, examples and a conversion table. PurpleMath.com features a tutorial on using dimensional analysis to convert many types of units to other units.