Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Imperial gallons to Litres
Convert imp gal to L instantly, then review the formula, assumptions, and rounding guidance.
VolumeInstant result
Decimals
Formula result = input × 4.54609 ÷ 1. 1 imp gal = 4.5461 L
Common examples
One value, several units
Litres4.5461 L
Millilitres4,546.09 mL
Cubic metres0.0045 m³
Cubic centimetres4,546.09 cm³
US gallons1.2009 US gal
US quarts4.8038 qt
US cups19.2152 cup
US fluid ounces153.7216 fl oz
Conversion table
| imp gal | L |
|---|---|
| 1 imp gal | 4.5461 L |
| 2 imp gal | 9.0922 L |
| 5 imp gal | 22.7305 L |
| 10 imp gal | 45.4609 L |
| 25 imp gal | 113.6523 L |
| 50 imp gal | 227.3045 L |
| 100 imp gal | 454.609 L |
Conversion chart
1 imp gal4.5461 L
5 imp gal22.7305 L
10 imp gal45.4609 L
25 imp gal113.6523 L
50 imp gal227.3045 L
Worked example
1 litre equals 1,000 millilitres.
Unit definition
Imperial gallons (imp gal) One imperial gallons equals 4.54609 litre.
Unit history
Imperial gallons is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert imp gal to litre.
3. Convert the base value to L and apply your display precision.
Understand the result before using it
Imperial gallons to Litres converts a value measured in Imperial gallons (imp gal) into the equivalent value in Litres (L). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 4.54609 ÷ 1
Assumptions
- Imperial gallons and Litres represent the same volume quantity.
- The input is expressed in imp gal; the output is expressed in L.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 imp gal = 4.54609 L. For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a imp gal measurement in a document that expects L.
- Compare a imperial gallons value with a value reported in litres.
- Check the imp gal-to-L arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- US gallons and imperial gallons are different units; select the one your source actually uses.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Imperial gallons to Litres?
result = input × 4.54609 ÷ 1 Using the displayed relationship, 1 imp gal equals 4.54609 L.
How many Litres are in one Imperial gallons?
One Imperial gallons is 4.54609 Litres. The displayed digits may be rounded.
Can I reverse the imp gal to L conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts L back to imp gal.
Is the Imperial gallons to Litres result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.