What is the difference between UK and US measurements?

UK and US imperial measurements differ for liquid volumes. A UK pint is 568ml while a US pint is only 473ml (20% smaller). UK gallons are 4.546 litres versus US gallons at 3.785 litres. Dry measurements and length measurements are identical between UK and US.

How do I quickly convert miles to kilometres?

Multiply miles by 1.6 for a quick estimate (or 8/5 for exact). So 50 miles × 1.6 = 80 km. For the reverse, divide kilometres by 1.6. The Fibonacci sequence also gives approximate conversions: 3 miles ≈ 5 km, 5 miles ≈ 8 km, 8 miles ≈ 13 km.

What temperature is 20 degrees Celsius in Fahrenheit?

20°C equals 68°F. The formula is (°C × 9/5) + 32 = °F. So (20 × 9/5) + 32 = 36 + 32 = 68°F. This is considered comfortable room temperature in most UK homes. For weather, 20°C is a pleasant spring or autumn day in Britain.

Conversion Chart Guide - Common Unit Conversions UK

Q: Why does the UK use both metric and imperial measurements?

The UK officially adopted the metric system in 1965 but retained imperial for certain uses. Road signs use miles, pubs serve pints, and people often discuss weight in stones. Shops must display metric weights, but can also show imperial. This dual system means conversion knowledge is essential for everyday life.

The UK uses a unique mix of metric and imperial measurements in daily life. While shops use kilograms and litres, we measure road distances in miles, drink pints at the pub, and often discuss our weight in stones. These comprehensive charts help you convert between measurement systems accurately.

Length Conversions

Length conversions are essential for DIY projects, understanding distances, and following recipes. The UK uses miles for road distances but centimetres and metres for most other measurements.

Imperial	Metric	Quick Mental Maths
1 inch	2.54 cm	× 2.5 for approximate cm
1 foot (12 inches)	30.48 cm	× 30 for approximate cm
1 yard (3 feet)	0.9144 m	Just under 1 metre
1 mile	1.609 km	× 1.6 or × 8 ÷ 5
5 miles	8.047 km	Approximately 8 km
10 miles	16.09 km	Approximately 16 km

Common UK Distances

Journey	Miles	Kilometres
London to Birmingham	120 miles	193 km
London to Manchester	200 miles	322 km
London to Edinburgh	400 miles	644 km
London to Glasgow	410 miles	660 km
Marathon distance	26.2 miles	42.195 km

Fibonacci Trick: The Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, 21...) provides quick mile-to-km conversions. Each number in miles roughly equals the next number in kilometres: 3 miles ≈ 5 km, 5 miles ≈ 8 km, 8 miles ≈ 13 km.

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Weight Conversions

The UK uses a mixture of metric (grams, kilograms) for retail and imperial (pounds, stones) for body weight. Understanding both is essential for cooking, shopping, and health.

Imperial	Metric	Quick Conversion
1 ounce (oz)	28.35 g	× 28 for grams
4 oz (quarter pound)	113.4 g	Approximately 110g
8 oz (half pound)	226.8 g	Approximately 225g
1 pound (lb) / 16 oz	453.6 g	Just under half a kg
1 stone (14 lb)	6.35 kg	× 6.35 for kg
1 hundredweight (cwt)	50.8 kg	Approximately 51 kg

Body Weight Reference (Stones to Kilograms)

Stones	Kilograms	Pounds
8 stone	50.8 kg	112 lb
10 stone	63.5 kg	140 lb
11 stone	69.9 kg	154 lb
12 stone	76.2 kg	168 lb
13 stone	82.6 kg	182 lb
14 stone	88.9 kg	196 lb
15 stone	95.3 kg	210 lb

Quick weight conversion: To convert stones to kilograms, multiply by 6.35. For a rough estimate, multiply stones by 6 and add half a stone's worth (3 kg) for each 10 stone.

Volume Conversions

Volume measurements in the UK are particularly confusing because we use metric for most liquids but serve beer in pints. Additionally, UK pints differ from US pints.

Imperial	Metric	Notes
1 teaspoon	5 ml	Standard measure
1 tablespoon	15 ml	3 teaspoons
1 fluid ounce (fl oz)	28.41 ml	UK measure
1 UK pint (20 fl oz)	568 ml	Larger than US pint
1 UK quart	1.137 litres	2 UK pints
1 UK gallon	4.546 litres	8 UK pints

UK vs US Volume Differences

Measurement	UK Volume	US Volume	Difference
Pint	568 ml	473 ml	UK 20% larger
Quart	1.137 L	0.946 L	UK 20% larger
Gallon	4.546 L	3.785 L	UK 20% larger
Fluid ounce	28.41 ml	29.57 ml	US 4% larger

American Recipe Warning: If following US recipes, remember their cups (240ml) differ from Australian cups (250ml). US pints and gallons are significantly smaller than UK equivalents. Always check which measurement system a recipe uses.

Temperature Conversions

The UK uses Celsius for weather but many people still think in Fahrenheit. Oven temperatures on older appliances may show Gas Marks, a uniquely British system.

Celsius	Fahrenheit	Common Use
-18°C	0°F	Freezer temperature
0°C	32°F	Water freezing point
10°C	50°F	Cool autumn day
15°C	59°F	Mild day
20°C	68°F	Room temperature
25°C	77°F	Warm summer day
30°C	86°F	Hot day (UK heatwave)
37°C	98.6°F	Human body temperature
40°C	104°F	Fever / UK record temp
100°C	212°F	Water boiling point

Oven Temperature Conversions

Gas Mark	Celsius	Fahrenheit	Description
¼	110°C	225°F	Very cool
½	120°C	250°F	Very cool
1	140°C	275°F	Cool
2	150°C	300°F	Cool
3	160°C	325°F	Moderate
4	180°C	350°F	Moderate
5	190°C	375°F	Moderately hot
6	200°C	400°F	Hot
7	220°C	425°F	Hot
8	230°C	450°F	Very hot
9	240°C	475°F	Very hot

Temperature Formula:
°F to °C: (°F - 32) × 5/9
°C to °F: (°C × 9/5) + 32
Quick estimate: Double Celsius and add 30 for approximate Fahrenheit

Area Conversions

Understanding area measurements is essential for property, gardening, and land transactions in the UK. While square metres are standard, acres are still commonly used for larger plots.

Imperial	Metric	Context
1 square inch	6.452 cm²	Small items
1 square foot	0.0929 m²	Room sizes (US)
1 square yard	0.8361 m²	Carpeting
1 acre	4,047 m²	Land measurement
1 acre	0.4047 hectares	Agricultural land
1 square mile	2.59 km²	Large areas
1 square mile	640 acres	Land surveys

Property Size Reference

Description	Square Feet	Square Metres
Average UK bedroom	120 sq ft	11 m²
Average UK living room	170 sq ft	16 m²
Average UK flat (1 bed)	500 sq ft	46 m²
Average UK house	970 sq ft	90 m²
Football pitch	76,854 sq ft	7,140 m²
Tennis court	2,808 sq ft	261 m²

Speed Conversions

The UK uses miles per hour for road speeds, but metric speeds are common elsewhere in Europe and for scientific purposes.

MPH	KPH	UK Context
20 mph	32 kph	School zones
30 mph	48 kph	Urban speed limit
40 mph	64 kph	Some A-roads
50 mph	80 kph	Roadworks on motorways
60 mph	97 kph	Single carriageway limit
70 mph	113 kph	Motorway/dual carriageway

Quick Speed Conversion: To convert mph to kph, multiply by 1.6. To convert kph to mph, multiply by 0.6. Example: 100 kph × 0.6 = 60 mph.

When to Use Which System

Imperial Still Used (UK)

Road distances and speeds: Miles and mph on all UK road signs
Beer and cider: Must be sold in pints or multiples at pubs
Body weight: Most Britons discuss weight in stones and pounds
Height: People typically give height in feet and inches
Land and property: Acres commonly used for larger plots

Metric Required (UK)

Packaged goods: All food labels must show metric weights
Petrol: Sold by the litre (though efficiency measured in mpg)
Medical settings: All measurements in metric
Construction: Building regulations use metric
Science and education: Exclusively metric

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Unit Conversion in the UK: Why It Matters

The UK's position between metric and imperial measurement systems makes conversion charts an essential everyday tool. Unlike most European countries that use metric exclusively, or the United States which primarily uses imperial, the UK uses a complex mixture of both. Road distances and speed limits are in miles, fuel is sold in litres, body weight is discussed in stone and pounds but recorded medically in kilograms, and temperatures can be given in either Celsius or Fahrenheit depending on the context.

This duality has practical consequences. The UK construction industry now works predominantly in metric (millimetres and metres), but many older buildings have plans in imperial measurements. UK cooking presents a particular challenge: BBC Good Food recipes use metric measurements, but many family recipe collections and older cookbooks use imperial cups, ounces, and fluid ounces. The UK pint (568ml) is larger than the US pint (473ml), which can cause confusion when following American recipes. Understanding conversions between systems is a practical life skill in Britain, whether you are renovating your home, following a new recipe, tracking your fitness goals, or shopping for goods online from international retailers.

Frequently Asked Questions About Conversion Charts

Why does the UK use both metric and imperial measurements?

The UK began transitioning to the metric system in 1965 but never completed the full changeover. Under EU regulations, most trade and commerce switched to metric units, but several imperial measurements were retained for everyday use by popular demand. Road signs and speed limits remain in miles (exempted by Parliament), draught beer and cider are sold in pints, and body weight is commonly given in stone and pounds. The result is a unique dual-system culture where most British people are comfortable working with both measurement systems, though younger generations tend to be more metric-focused.

What is the difference between a UK gallon and a US gallon?

A UK (imperial) gallon equals 4.546 litres, while a US gallon equals only 3.785 litres. This means a UK gallon is approximately 20% larger than a US gallon. The difference stems from different historical definitions: the imperial gallon was defined as the volume of 10 pounds of water, while the US gallon was based on the older English wine gallon. This distinction is important when comparing fuel economy figures, as UK miles per gallon figures will always be higher than US mpg for the same vehicle due to the larger gallon size.

How do I convert UK clothing sizes to European or US sizes?

UK clothing sizes differ from both European and US sizing systems. For women, a UK size 10 is roughly equivalent to a US size 6 and a European size 38. For men, a UK shirt collar size of 15.5 inches corresponds to a European size 39-40. UK shoe sizes also differ: a UK men's size 9 is a US size 10 and a European size 43. There is no universal standard across brands, so sizes can vary. When shopping online from international retailers, always check the specific size chart provided by the brand rather than relying solely on general conversion tables.

Why does the UK use a mix of metric and imperial measurements?

The UK officially adopted the metric system for most purposes through the Weights and Measures Act 1985 and subsequent EU directives, but imperial measurements remain deeply embedded in everyday life. Road signs display distances in miles, speed limits are in miles per hour, and pubs serve beer and cider in pints. Body weight is commonly expressed in stones and pounds, and height in feet and inches. This dual system exists because metrication in the UK was never fully completed, unlike in most other European countries. Grocers can display prices in both metric and imperial, and many older recipes use imperial measures. Understanding both systems and being able to convert between them remains an essential everyday skill for UK residents.

What are the most common conversion mistakes people make in the UK?

The most frequent conversion error in the UK involves confusing US and UK (imperial) measurements that share the same name but differ in size. A US gallon is approximately 3.785 litres, while a UK imperial gallon is approximately 4.546 litres, nearly 20 percent larger. Similarly, a US fluid ounce differs from a UK fluid ounce. Another common mistake is confusing metric tonnes (1,000 kg) with imperial tons (1,016 kg for a long ton or 907 kg for a short ton). People also regularly mix up nautical miles with statute miles when planning sea crossings or flights. When following American recipes in a UK kitchen, cup measurements cause confusion because US cups and UK cups are different sizes. Always verify which system a measurement belongs to before converting.

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Emma Thompson

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Emma is a senior content editor with a background in financial journalism. She specialises in making UK regulations and calculator tools understandable for consumers, working closely with qualified professionals to ensure accuracy.