Gallons to Litres (UK) Converter 2026 | Unit Conversion Calculator
Gallons to Litres (UK) Converter 2026
Accurate UK Imperial Gallon to Litre Conversion
Professional Volume Unit Conversion Calculator
The UK Imperial gallon is the standard volume measurement used in the United Kingdom for fuel, beverages, and other liquids. Our gallons to litres converter provides accurate conversions between UK gallons and litres using the official conversion factor: 1 UK gallon = 4.54609 litres. This differs from the US gallon, making accurate conversion essential for international trade and travel.
Whether you're calculating fuel consumption, converting recipes, or working with liquid measurements in construction and engineering, this UK gallons to litres calculator ensures precision. Understanding the difference between UK and US liquid measurements prevents costly errors in commerce and daily life.
🧮 Gallons to Litres Calculator
Convert between UK Imperial gallons and litres instantly
Volume Conversion
Converted Volume
0 L
-
Common Conversions
Millilitres (mL)
0 mL
Pints (UK)
0 pints
Fluid Ounces (UK)
0 fl oz
Cubic Metres
0 m³
Conversion Details
Conversion Factor1 UK gal = 4.54609 L
Measurement SystemUK Imperial
Precision5 decimal places
Understanding UK Gallons and Litres 2026
The UK Imperial gallon has been the standard volume measurement in Britain since 1824, defined as the volume of 10 pounds of water at 62°F (277.42 cubic inches). The litre, part of the International System of Units (SI), is defined as one cubic decimetre (1000 cubic centimetres). While the UK officially adopted metric measurements, gallons remain commonly used for fuel and draught beverages.
✅ Key Conversion Facts:
1 UK Imperial gallon = 4.54609 litres (exact)
1 litre = 0.219969 UK gallons
1 UK gallon = 8 UK pints = 160 UK fluid ounces
UK gallon is 20% larger than US gallon (3.785 litres)
Temperature-independent modern definition since 1985
Quick Conversion Table: Gallons to Litres
UK Gallons
Litres
Millilitres
Common Use
0.5 gal
2.27 L
2,273 mL
Small container
1 gal
4.55 L
4,546 mL
Standard gallon
2 gal
9.09 L
9,092 mL
Medium container
5 gal
22.73 L
22,730 mL
Large container
10 gal
45.46 L
45,461 mL
Fuel tank (motorcycle)
15 gal
68.19 L
68,191 mL
Car fuel tank
20 gal
90.92 L
90,922 mL
Large fuel tank
50 gal
227.30 L
227,305 mL
Storage drum
100 gal
454.61 L
454,609 mL
Large tank
200 gal
909.22 L
909,218 mL
Commercial storage
1 UK Gallon
Litres4.55 L
Millilitres4,546 mL
UseStandard gallon
5 UK Gallons
Litres22.73 L
Millilitres22,730 mL
UseLarge container
15 UK Gallons
Litres68.19 L
Millilitres68,191 mL
UseCar fuel tank
100 UK Gallons
Litres454.61 L
Millilitres454,609 mL
UseLarge tank
Litres to Gallons Conversion Table
Converting litres back to UK gallons is equally important for international specifications and comparing fuel economy figures. The conversion factor remains 1 litre = 0.219969 UK gallons.
Litres
UK Gallons
UK Pints
Common Application
1 L
0.22 gal
1.76 pints
Bottle size
5 L
1.10 gal
8.80 pints
Large bottle
10 L
2.20 gal
17.60 pints
Medium container
20 L
4.40 gal
35.20 pints
Jerry can
50 L
11.00 gal
88.00 pints
Fuel tank
100 L
22.00 gal
176.00 pints
Large fuel tank
200 L
43.99 gal
351.95 pints
Oil drum
500 L
109.98 gal
879.88 pints
IBC container
1,000 L
219.97 gal
1,759.75 pints
Cubic metre
1 Litre
UK Gallons0.22 gal
UK Pints1.76 pints
UseBottle size
20 Litres
UK Gallons4.40 gal
UK Pints35.20 pints
UseJerry can
100 Litres
UK Gallons22.00 gal
UK Pints176.00 pints
UseLarge fuel tank
1,000 Litres
UK Gallons219.97 gal
UK Pints1,759.75 pints
UseCubic metre
UK vs US Gallons: Key Differences
One of the most common sources of confusion in volume measurement is the difference between UK Imperial gallons and US liquid gallons. Understanding these distinctions is crucial for international trade, travel, and accurate conversion calculations.
UK Imperial Gallon
Volume: 4.54609 litres
Cubic inches: 277.42 in³
Definition: 10 pounds of water at 62°F (historical)
Subdivisions: 8 pints, 160 fluid ounces
Usage: UK, Ireland, some Commonwealth nations
US Liquid Gallon
Volume: 3.78541 litres
Cubic inches: 231 in³ (exact)
Definition: 231 cubic inches by law
Subdivisions: 8 pints, 128 fluid ounces
Usage: United States, some Latin American countries
Percentage Difference
UK vs US: UK gallon is 20.1% larger
Ratio: 1 UK gallon = 1.201 US gallons
Fuel Economy: 40 mpg (UK) = 33.3 mpg (US)
Impact: Significant for fuel consumption comparisons
Note: Always specify which gallon system when converting
⚠️ Important Conversion Note:
When converting between UK and US measurements, always verify which gallon type is being referenced. Fuel economy figures, container capacities, and recipe volumes can differ significantly. For example, a 15-gallon fuel tank in the UK holds 68.2 litres, while a 15-gallon US tank holds only 56.8 litres—an 11.4-litre difference that could affect range calculations and fuel planning.
Common Uses for Gallons to Litres Conversion
Accurate volume conversion between gallons and litres is essential in numerous practical applications across multiple industries and everyday situations.
Fuel and Automotive
Fuel consumption: Converting mpg (miles per gallon) to L/100km or comparing UK vs European fuel economy figures
Fuel tank capacity: Understanding vehicle specifications when travelling internationally or importing vehicles
Fuel pricing: Comparing petrol/diesel prices per litre vs per gallon for accurate cost calculations
Fleet management: Calculating total fuel requirements for commercial vehicle operations
Construction and Engineering
Liquid materials: Converting paint, adhesives, coatings, and sealant quantities from supplier specifications
Water management: Calculating tank capacities, water usage, and drainage system volumes
Chemical dosing: Precise conversion for water treatment, concrete additives, and construction chemicals
Project estimation: Accurate material ordering to prevent shortages or excess waste
Food and Beverage Industry
Recipe conversion: Adapting American recipes (US gallons) to UK or metric measurements
Brewing and distilling: Converting batch sizes and ingredient volumes accurately
Commercial catering: Scaling recipes up or down while maintaining correct proportions
Irrigation systems: Calculating water flow rates and daily water requirements per hectare
Chemical application: Converting pesticide, herbicide, and fertilizer mixing ratios accurately
Tank mixing: Preparing correct spray volumes for agricultural machinery and equipment
Storage planning: Determining appropriate tank sizes for water storage and liquid feed systems
Conversion Formula and Calculation Method
Understanding the mathematical relationship between UK gallons and litres enables manual conversion when calculators aren't available and helps verify automated calculations.
📐 Conversion Formulas:
Gallons to Litres: Litres = UK Gallons × 4.54609
Litres to Gallons: UK Gallons = Litres × 0.219969
Alternative (Litres to Gallons): UK Gallons = Litres ÷ 4.54609
Gallons to Millilitres: Millilitres = UK Gallons × 4546.09
Quick estimation: 1 UK gallon ≈ 4.5 litres (2% error)
Worked Examples
Example 1: Fuel Tank
Question: Convert 12 UK gallons to litres
Calculation: 12 × 4.54609 = 54.55308 litres
Answer: 54.55 litres (rounded to 2 decimal places)
Question: 5 UK gallons of paint converts to how many litres?
Calculation: 5 × 4.54609 = 22.73045 litres
Answer: 22.73 litres
Practical use: Approximately 23 litres for ordering purposes
Historical Context of UK Imperial Gallon
The UK Imperial gallon has a rich history dating back to medieval England, evolving through various standardizations before reaching its modern definition in the 19th century.
📜 Historical Timeline:
Medieval period: Various regional gallon definitions existed across England, causing trade confusion
1707: Queen Anne's wine gallon (231 cubic inches) used for wine and spirits
1824: Weights and Measures Act established Imperial gallon as 10 pounds of water at 62°F
1985: Redefined using metric system as exactly 4.54609 cubic decimetres (litres)
Present: Still legal for road signs, fuel sales, and draught beverages in UK despite metrication
The Imperial gallon was designed to be easy to subdivide: 1 gallon = 4 quarts = 8 pints = 160 fluid ounces. This system remains deeply embedded in British culture, particularly in pub measures (pints of beer), fuel economy metrics (miles per gallon), and traditional measurements passed down through generations.
Legal Requirements and Standards 2026
In the UK, legal requirements for volume measurement vary by application. The Weights and Measures Act and associated regulations govern when gallons, litres, or both must be displayed.
Product/Service
Required Unit
Supplementary Unit
Notes
Petrol/Diesel Forecourt
Litres
Gallons (optional)
Prices must be per litre
Draught Beer/Cider (Pubs)
Pints/Half-Pints
Millilitres (optional)
Imperial pint (568ml) mandatory
Bottled Beverages
Millilitres/Litres
Fluid ounces (optional)
Metric only for pre-packaged
Road Signs (Distance)
Miles
Not applicable
Miles and yards remain official
Fuel Consumption (Advertising)
Litres/100km
mpg (common practice)
Both often displayed for clarity
Commercial Containers
Litres
Gallons (common)
Metric required, imperial traditional
Petrol/Diesel Forecourt
Required UnitLitres
SupplementaryGallons (optional)
NotePrices per litre mandatory
Draught Beer/Cider
Required UnitPints/Half-Pints
SupplementaryMillilitres (optional)
Note568ml pint mandatory
Fuel Consumption
Required UnitLitres/100km
Supplementarympg (common)
NoteBoth often displayed
Gallons to Litres Converter FAQs
How many litres are in a UK gallon?
One UK Imperial gallon equals exactly 4.54609 litres. This is the official conversion factor defined by international standards. The UK gallon is significantly larger than the US gallon (3.785 litres), which is why it's crucial to specify which gallon system you're using when converting volumes.
What is the difference between UK and US gallons?
The UK Imperial gallon contains 4.54609 litres, while the US liquid gallon contains 3.78541 litres. This means the UK gallon is approximately 20% larger than the US gallon. This difference originated from different historical definitions: the UK gallon was defined as 10 pounds of water, while the US gallon was defined as 231 cubic inches.
How do I convert 5 gallons to litres?
To convert 5 UK gallons to litres, multiply by 4.54609: 5 × 4.54609 = 22.73045 litres (approximately 22.73 L). For US gallons, you would multiply by 3.78541 instead, giving 18.93 litres. Always verify which gallon measurement system is being used before converting.
Is petrol sold in litres or gallons in the UK?
Since 1995, petrol and diesel in the UK have been sold in litres at forecourts, with prices displayed per litre. However, fuel consumption is still commonly expressed in miles per gallon (mpg) for traditional reasons. New vehicles must display fuel consumption in litres per 100 kilometres (L/100km) alongside mpg figures.
How many litres in 10 gallons?
10 UK gallons equals 45.4609 litres (45.46 L when rounded). For US gallons, 10 gallons equals 37.8541 litres (37.85 L). This significant difference—7.6 litres—demonstrates why specifying the gallon type is essential, particularly for fuel tank capacities and consumption calculations.
Why does the UK still use gallons for some things?
The UK officially adopted metric measurements in the 1960s-1990s, but retained Imperial units for specific traditional applications: road distances (miles), beer and milk in returnable containers (pints), and cultural preference for miles per gallon. This dual system reflects British heritage while conforming to EU and international trade requirements for metric measurements in most commercial contexts.
How many litres are in a pint UK?
One UK Imperial pint equals 0.568261 litres (approximately 568 millilitres). Since there are 8 pints in a UK gallon, dividing 4.54609 litres by 8 gives this value. The UK pint is larger than the US pint (473 mL), which is why British pub pints provide more beer than their American equivalents.
Can I use this converter for US gallons?
This calculator is specifically designed for UK Imperial gallons (4.54609 L). For US liquid gallons, use the conversion factor 3.78541 litres per gallon instead. Using the wrong conversion factor will result in approximately 20% error in your calculations, which can be significant for fuel economy, tank capacities, and recipe conversions.
What is the most accurate way to convert gallons to litres?
The most accurate method is to use the official conversion factor: multiply UK gallons by 4.54609 (or litres by 0.219969 for reverse conversion). This factor is defined by international standards and provides accuracy to 5 decimal places. For rough estimates, 4.5 litres per gallon is acceptable but introduces about 2% error.
How many gallons in 100 litres?
100 litres equals 21.9969 UK Imperial gallons (approximately 22.0 gallons). This is calculated by multiplying 100 × 0.219969, or alternatively dividing 100 by 4.54609. For comparison, 100 litres equals 26.42 US gallons, demonstrating again the importance of specifying which gallon measurement system you're using.
