Imperial gallon to Cubic decimeter

imp gal

1 imp gal

dm³

4.54608999998115 dm³

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Quick Reference Table (Imperial gallon to Cubic decimeter)

Imperial gallon (imp gal)Cubic decimeter (dm³)
0.52.273044999990575
14.54608999998115
29.0921799999623
522.73044999990575
1045.4608999998115
50227.3044999990575

About Imperial gallon (imp gal)

The imperial gallon is a unit of volume defined as exactly 4.54609 liters, used in the United Kingdom, Canada, and some Commonwealth nations. It is approximately 20% larger than the US liquid gallon. Fuel economy in the UK is expressed in miles per imperial gallon. The imperial gallon divides into 8 imperial pints, each of 568 mL. The UK officially metricated fuel sales to liters in the 1980s–1990s, but miles per imperial gallon remains the legal unit for new car fuel economy labels.

UK car fuel economy figures are expressed in miles per imperial gallon. One imperial gallon equals 8 standard UK pints of beer.

About Cubic decimeter (dm³)

A cubic decimeter (dm³) is the volume of a cube with sides of 10 centimeters, exactly equal to one liter (1 dm³ = 1 L). This equivalence is exact and defined by the SI. The cubic decimeter appears in physics and chemistry textbooks as the formal SI expression of volume where liters are used in practice, and in engineering calculations requiring dimensional consistency. One dm³ of pure water at 4°C has a mass of exactly one kilogram.

A standard 1-liter water bottle contains exactly 1 dm³. A typical lunchbox has a volume of roughly 2–3 dm³.


Imperial gallon – Frequently Asked Questions

One imperial gallon is defined as exactly 4.54609 liters — approximately 20% more than the US liquid gallon (3.785 L).

The UK switched fuel sales to liters in the 1990s. However, miles per gallon (imperial) remains the legal unit for car fuel economy on new vehicle labels. Road speed is in mph and distances are in miles, so imperial gallons remain embedded in UK motoring.

UK MPG uses the imperial gallon (4.546 L); US MPG uses the US gallon (3.785 L). Multiply UK MPG by 0.832 to get US MPG. A car rated 40 UK MPG ≈ 33 US MPG.

There are exactly 8 imperial pints in one imperial gallon. Each imperial pint is 568 mL, compared to 473 mL for a US pint.

Canada officially metricated in the 1970s and fuel is sold in liters. However, some older Canadians and certain agricultural contexts still reference imperial gallons informally. Canadian and UK imperial gallons are identical (4.54609 L).

Cubic decimeter – Frequently Asked Questions

Yes, exactly. One cubic decimeter (dm³) is defined as equal to one liter (L). This is the foundational link between the cubic metric system and the liter-based system used in everyday measurement.

In formal SI notation, volume is expressed in cubic meters or submultiples like dm³. The liter is accepted but technically non-SI. Chemistry texts use dm³ to maintain dimensional consistency, though liter and dm³ are completely interchangeable.

There are 1,000 cubic decimeters in one cubic meter (m³), because 1 m = 10 dm and 10³ = 1,000. This also means 1 m³ = 1,000 liters.

One cubic decimeter equals 1,000 cubic centimeters (cm³). Since 1 cm³ = 1 mL, it follows that 1 dm³ = 1 L = 1,000 mL — fully consistent within the metric system.

The cubic decimeter appears primarily in scientific and educational contexts, particularly chemistry and physics where SI units are preferred. In everyday life, the liter is used instead — but they refer to the same volume.

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