Convert between UK imperial and metric units instantly. Our comprehensive calculator handles length, weight, volume, temperature, and area conversions commonly used in the United Kingdom.
The United Kingdom uses a unique hybrid measurement system. While officially metric since the Weights and Measures Act 1985, imperial units remain deeply embedded in daily life. This dual system reflects the UK's gradual transition from imperial measurements—based on the Weights and Measures Act 1824—to the metric system adopted across the European Union.
Legal Imperial Units in the UK (2024): Road distances and speed limits (miles, mph), draught beer and cider in pubs (pints), milk in returnable containers, precious metals (troy ounces), and body weight (stones and pounds informally). Since 2022, shops may display imperial units alongside metric.
Metric-Only Areas: All packaged goods, scientific measurements, medical prescriptions, building materials, and official trade. The metric system is taught exclusively in UK schools.
| Imperial UK | Metric Metric | Common Use |
|---|---|---|
| 1 inch | 2.54 cm | Screen sizes, rainfall |
| 1 foot | 30.48 cm | Height, room dimensions |
| 1 yard | 0.9144 m | Fabric, sports |
| 1 mile | 1.60934 km | Road distances |
| 5 miles | 8.047 km | 5K race equivalent |
| 26.2 miles | 42.195 km | Marathon |
| Imperial UK | Metric Metric | Common Use |
|---|---|---|
| 1 ounce (oz) | 28.35 g | Recipes, precious metals |
| 1 pound (lb) | 453.59 g | Baby weight, groceries |
| 1 stone (st) | 6.35 kg | Body weight |
| 14 stone | 88.9 kg | Average UK man |
| 10 stone | 63.5 kg | Average UK woman |
| 1 UK ton (long) | 1016.05 kg | Shipping, heavy loads |
| Imperial UK | Metric Metric | Common Use |
|---|---|---|
| 1 UK fluid ounce | 28.41 ml | Cooking, spirits |
| 1 UK pint | 568.26 ml | Beer, milk |
| 1 UK gallon | 4.546 litres | Fuel efficiency |
| 1 US pint | 473.18 ml | American recipes |
| 1 US gallon | 3.785 litres | US fuel prices |
| 2 UK pints | 1.137 litres | Milk cartons |
⚠️ Important: UK pints are 20% larger than US pints. This affects cooking and fuel economy comparisons.
| Description | Celsius (°C) | Fahrenheit (°F) |
|---|---|---|
| Water freezing point | 0°C | 32°F |
| Cold winter day (UK) | 2°C | 36°F |
| Cool spring day | 10°C | 50°F |
| Room temperature | 20°C | 68°F |
| Hot summer day (UK) | 30°C | 86°F |
| Body temperature | 37°C | 98.6°F |
| Water boiling point | 100°C | 212°F |
| Gas Mark 4 (oven) | 180°C | 350°F |
| Gas Mark 6 (oven) | 200°C | 400°F |
| Imperial UK | Metric Metric | Context |
|---|---|---|
| 1 square foot | 0.0929 m² | Room sizes |
| 100 sq ft | 9.29 m² | Small bedroom |
| 818 sq ft | 76 m² | Average UK home |
| 1,076 sq ft | 100 m² | Larger house |
| 1 acre | 4,047 m² | Land/gardens |
| 1 hectare | 10,000 m² | Farming land |
| 1 square mile | 2.59 km² | Town/city area |
| Location | Speed (mph) | Speed (km/h) |
|---|---|---|
| Built-up areas (default) | 30 mph | 48 km/h |
| Single carriageway | 60 mph | 97 km/h |
| Dual carriageway | 70 mph | 113 km/h |
| Motorway | 70 mph | 113 km/h |
| 20 mph zones | 20 mph | 32 km/h |
💡 Tip: When driving in Europe, multiply mph by 1.6 to get km/h. The UK is one of only three countries worldwide (with USA and Myanmar) still using mph on roads.
Part of the Department for Business and Trade, responsible for UK measurement policy and enforcement.
GOV.UK - Weights & Measures →The UK's National Metrology Institute, responsible for measurement science and standards.
NPL - National Standards →The primary legislation governing units of measurement for trade in the UK.
Legislation.gov.uk →Royal Institution of Chartered Surveyors standards for measuring property floor areas.
RICS Property Standards →UK's national weather service using Celsius for all temperature measurements and forecasts.
Met Office Weather →Information on UK beer measures and the legal requirement for pint glasses.
BBPA - UK Pubs →This comprehensive UK unit converter is designed specifically for British users who regularly need to convert between imperial and metric measurements. Whether you're calculating your weight for a medical appointment, converting a recipe from an American cookbook, understanding property floor areas, or comparing fuel efficiency between UK and US vehicles, our calculator provides instant, accurate results.
All conversions use the official conversion factors defined by the UK Weights and Measures Act 1985 and international SI standards. The calculator distinguishes between UK imperial and US customary units—a crucial difference often overlooked by generic converters. For example, we correctly calculate that a UK pint equals 568.261ml (not the US 473ml), and a UK gallon equals 4.546 litres (not the US 3.785 litres).
Created and maintained by Mustafa Bilgic, this tool is part of the UK Calculator suite—free, privacy-focused calculators designed specifically for United Kingdom residents. All calculations are performed locally in your browser; no data is sent to any server.
Last updated: January 2026 | Verified with latest UK rates
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