Convert lengths instantly between metric and imperial units - metres to feet, centimetres to inches, and more. Essential for UK construction, DIY, property measurements, and everyday conversions between the UK's dual measurement systems.
This converter uses official UK conversion factors: 1 metre = 3.28084 feet exactly, 1 inch = 2.54 centimetres exactly. Perfect for construction drawings, furniture dimensions, screen sizes, and DIY projects that bridge metric and imperial measurements.
The United Kingdom operates a unique dual system where both metric and imperial units remain in everyday use. While the UK officially adopted the metric system in 1965, imperial measurements were never fully phased out. Today, road signs display miles, property dimensions are quoted in square feet, but construction plans use millimetres, and fuel is sold in litres.
These are the precise conversion factors defined by the UK Weights and Measures Act 1985 and still valid in 2024:
| Metres | Centimetres | Feet | Inches |
|---|---|---|---|
| 0.1 m | 10 cm | 0.33 ft | 3.94 in |
| 0.5 m | 50 cm | 1.64 ft | 19.69 in |
| 1 m | 100 cm | 3.28 ft | 39.37 in |
| 2 m | 200 cm | 6.56 ft | 78.74 in |
| 3 m | 300 cm | 9.84 ft | 118.11 in |
| 5 m | 500 cm | 16.40 ft | 196.85 in |
| 10 m | 1,000 cm | 32.81 ft | 393.70 in |
Construction and Building (2024 Standards): UK Building Regulations use metric units exclusively - all measurements in millimetres. However, timber is often sold in imperial sizes (2×4 inches, 4×4 inches), and plasterboard comes in 8-foot or 10-foot sheets. Architects provide metric drawings, but builders mentally convert to feet and inches on site.
Property and Real Estate: Estate agents advertise properties in square feet, even though official Land Registry documents use square metres. A typical UK 3-bedroom house is described as "1,200 square feet" in marketing, but planning applications must use metric. Room dimensions are often quoted in both: "Master bedroom: 4.5m × 3.8m (14'9" × 12'6")".
DIY and Home Improvement: UK DIY stores price timber by the foot but specify thickness in millimetres (e.g., "8-foot length, 18mm thickness"). Rawlplugs and screws use metric sizes (6mm, 8mm), but drill bits are available in both metric and imperial. Paint coverage is listed per square metre, but rooms are measured in feet.
Screen Sizes and Electronics: TV screens, computer monitors, and smartphone displays are universally measured in inches in the UK, even though packaging must show metric equivalents. A "55-inch TV" is also labelled "139.7 cm diagonal", but nobody uses the metric measurement in conversation.
Clothing and Textiles: UK clothing sizes use inches for waist measurements (32-inch waist), but EU sizes are also shown. Fabric is sold by the metre in UK shops, though older patterns may reference yards. Inside leg measurements for trousers are quoted in inches (30", 32", 34").
UK schools teach the metric system exclusively from Key Stage 2 onwards (ages 7+), in line with the national curriculum 2024. However, GCSE maths exams include questions on converting between metric and imperial units, recognising that pupils will encounter both systems in daily life. Common exam questions involve converting speeds (mph to km/h) and lengths (cm to inches).
For most practical purposes, converting to 2 decimal places is sufficient (e.g., 1.5m = 4.92 feet). Construction work typically uses 1mm precision for metric or 1/16 inch for imperial. Engineering and manufacturing may require greater accuracy - CNC machining works to 0.01mm tolerances, aerospace to 0.001mm (1 micron).
The UK began metrication in 1965, but implementation was piecemeal. Decimalisation of currency in 1971 removed pounds, shillings, and pence. Road signs remain in miles due to the cost of replacement (estimated £750 million in 2024). The Weights and Measures Act 1985 requires metric units for trade, but imperial units remain legal for specific applications like draught beer and milk in pints.
1. Master the key conversion factors: 1 metre = 3.28084 feet (not 3.3), 1 foot = 30.48 cm (exactly), 1 inch = 2.54 cm (exactly). These are international standards set in 1959. For quick mental math: 1m ≈ 3.3ft, 1ft ≈ 30cm, but use exact factors for precision work.
2. UK construction requires millimetres: All UK Building Regulations drawings use mm as standard unit (e.g., 2400mm, not 2.4m). When buying materials, convert your measurements: 8-foot sheet = 2438mm (round to 2440mm standard size). Architectural drawings never mix units.
3. Property measurements strategy: UK estate agents advertise in square feet (\"1,200 sq ft\") but Land Registry documents use square metres. For room dimensions: measure in metres with laser measure, calculate area in m², then convert to sq ft for comparisons (multiply m² by 10.764). A 100m² property = 1,076 sq ft.
4. DIY lumber conversions: UK timber sold in metric lengths (1.8m, 2.4m, 3.0m, 4.8m) but cross-sections labeled imperially (2×4, 4×2). A 2×4 stud is actually 38mm × 89mm after planing (not 2\" × 4\"). For fence posts, 100mm × 100mm = 4\" × 4\" nominal. Always check actual vs nominal dimensions.
5. International furniture shopping: IKEA, Wayfair, and EU retailers list dimensions in cm. UK property ads describe rooms in feet (\"12ft × 10ft living room\"). Convert your room: 12ft = 3.66m, 10ft = 3.05m. A 200cm (78.7\") sofa fits comfortably with 1m+ clearance. Measure doorways too - UK internal doors 762mm (30\") wide.
6. Garden and landscaping: UK garden centres sell decking in metres, but fence panels in feet (6ft = 1.83m is standard panel width). Turf/topsoil prices per square metre. Paving slabs: 600mm × 600mm or 450mm × 450mm (metric). Convert garden measurements to single unit to avoid errors - either all metres or all feet.
7. Sports field dimensions: UK football pitches use metres (FIFA standard: 100-110m long, 64-75m wide). Rugby union also metric. However, cricket pitches: 22 yards (20.12m) between wickets - imperial legacy. Tennis courts: 78ft long, 27ft wide singles (23.77m × 8.23m) - international standard still feet.
8. Precision carpentry and joinery: UK craftsmen think in millimetres for cuts: \"Cut at 450mm\" not \"45cm\". Fractional inches for traditional joinery: 1/16\" = 1.588mm tolerance. Modern CNC machines work in 0.1mm increments. For DIY, ±2mm accuracy sufficient; professional joinery requires ±0.5mm.
9. International travel height limits: EU tunnel/bridge signs show metres (e.g., \"3.5m height limit\"). UK road signs show feet/inches (\"13'6\" height limit\"). Motorhome/van owners must know vehicle height in both. Example: 3.2m vehicle = 10.5 feet. Always add 0.3m/1ft safety margin for aerials/roof racks.
Mistake 1: Using approximations for critical measurements. \"1 metre = 3 feet\" is close but wrong (actual: 3.28ft = 3ft 3.37in). For a 10-metre fence, 3ft/m gives 30ft (wrong), actual is 32.8ft (32ft 9.6in). This 2.8ft error means buying wrong materials. Always use 3.28084 for calculations, approximate only for quick estimates.
Mistake 2: Mixing metric and imperial in calculations. UK construction drawings show 2440mm width, but you measure 7 feet. Can't compare directly - convert first. 7ft = 2133.6mm (too short). Or convert drawing: 2440mm = 8.005ft. Never calculate \"2440 - 7\" thinking it's valid. Always use consistent units throughout.
Mistake 3: Confusing decimal feet with feet-inches. 5.5 metres = 18.04 feet decimal, NOT 18 feet 5 inches. 18.04ft = 18ft + (0.04 × 12) inches = 18ft 0.5in. Many converters show 18.04ft without clarifying. To get feet-inches: integer part = feet, decimal × 12 = inches. 18.04 × 12 = 216.5 inches = 18 feet 0.5 inches.
Mistake 4: Forgetting UK standard sizes differ from metric. UK plasterboard: \"8 by 4\" sheet is 2400mm × 1200mm (actually 7.87ft × 3.94ft), not exactly 8ft × 4ft. UK door heights: 1981mm (6ft 6in) standard, 2040mm (6ft 8in) tall doors. These are compromises between metric (2000mm, 2100mm) and imperial (6ft 6in, 7ft) - don't assume round numbers.
Mistake 5: Using wrong area conversion factors. Square metres to square feet is NOT metres-to-feet factor (3.28) - it's 3.28² = 10.764. Example: 20m² room = 20 × 10.764 = 215.3 sq ft, not 20 × 3.28 = 65.6 (wrong). Area conversions square the length factor. Volume conversions cube it (1m³ = 35.315 cubic feet).
Mistake 6: Not accounting for measurement units on tools. UK tape measures show cm one side, inches reverse. Easy to read wrong side - 30cm reads as 11.8\" on flip side. Digital laser measures default to metres - change to feet if needed. Older UK rulers may show obsolete Imperial inches (pre-1959: 1 inch = 25.4000508mm, now 25.4mm exactly).
Mistake 7: Rounding intermediate steps. Converting 6.5 feet to metres: don't round 6.5ft to 7ft first (gives 2.13m), calculate 6.5 × 0.3048 = 1.98m directly. For 100-foot length, rounding each 10ft segment compounds error. Always convert final measurement, not intermediate steps. Precision: 2 decimals for construction, 3-4 for engineering.
Mistake 8: Ignoring tolerance requirements. UK Building Regs Part L (insulation) requires mm accuracy. Kitchen fitting needs ±2mm tolerance. General DIY: ±5mm acceptable. Saying \"about 3 metres\" is fine for garden design but unacceptable for window fitting. Professional trades work to ±1mm for critical dimensions (door frames, window reveals).
The UK's dual measurement system results from incomplete metrication. The Metrication Board (1969-1980) switched most sectors to metric, but was disbanded before completion. Road signs, property sales, and personal measurements retained imperial. Today, anyone in the UK must be fluent in both systems - metric for official/technical use, imperial for everyday descriptions and historical context.
International Yard and Pound Agreement (1959) - UK, USA, Canada, Australia, NZ, South Africa adopted these exact definitions:
Before 1959, the British Imperial inch (2.53998cm) differed slightly from the US inch (2.540005cm). This tiny difference caused problems for international engineering and trade. The 1959 agreement unified measurements worldwide and is still the global standard.
| Application | Units Used | UK Standards |
|---|---|---|
| Building Regulations | Millimetres (mm) | All UK Building Regs 1995+ use metric. Minimum room heights: 2300mm (7.5ft) |
| Property Sales | Square feet (sq ft) | Estate agents advertise in sq ft. Land Registry documents use m² |
| Road Distances | Miles and yards | UK road signs legally required to show miles. Speed limits in mph |
| Personal Height | Feet and inches | Passports/licenses use cm, but people think in feet-inches (\"5'10\"\") |
| Timber/Lumber | Metric lengths, imperial cross-sections | Sold in 2.4m, 3.0m lengths. Described as 2×4, 4×2 (actual: 38×89mm) |
| Textiles/Fabric | Metres | UK fabric shops sell by the metre. Older patterns may reference yards |
| Screen Sizes | Inches (diagonal) | TVs, monitors, phones worldwide use inches. UK packaging shows cm too |
| Sports Fields | Mixed: football metres, cricket yards | FIFA uses metres. Cricket pitch: 22 yards between wickets (historical) |
UK Standard Measurements (2024):
Construction: ±5mm tolerance general, ±2mm for joinery, ±1mm for kitchen fitting. UK Building Control checks measurements during inspections - non-compliance requires remedial work.
Engineering: Mechanical engineering: ±0.1mm typical, ±0.01mm precision machining. Aerospace: ±0.001mm (1 micron) for critical components. Use digital calipers, not tape measures.
Surveying: Land surveys: ±10mm over 100m (Ordnance Survey standards). Property boundaries: ±50mm acceptable. Professional surveyors use total stations (accuracy ±1mm + 1ppm).
DIY/Home Improvement: ±10mm acceptable for most projects. Tile laying: ±2mm per tile, grout lines even out errors. Garden landscaping: ±50mm fine for paths, ±20mm for patios.
UK Building Regulations (approved documents A-Q) specify measurements in millimetres for all structural elements. Part A (Structure) defines minimum dimensions: load-bearing walls 190mm thick minimum, floor joists calculated per span tables in mm. Part K (Stairs) specifies risers 150-220mm, goings 220mm minimum, handrails 900-1000mm height. Part M (Accessibility) requires doorways 775mm clear width minimum, corridors 1200mm wide for wheelchair access.
Tolerance standards: BS EN ISO 9001 (quality management) applies to UK construction. Typical tolerances: foundations ±25mm, floor levels ±15mm, wall verticality ±10mm per 3m height, door openings ±3mm, kitchen units ±2mm. Professional builders use laser levels (±1mm accuracy), rotary lasers for site leveling, and digital calipers for precision work. DIY tape measures (Class II accuracy ±2mm per metre) acceptable for general work but not fine joinery.
Laser distance measurers (Bosch GLM, Leica Disto, Makita LD) are standard tools for UK surveyors, architects, and tradespeople. Accuracy: ±1-2mm up to 100m range. Measure directly to nearest mm, calculate areas and volumes instantly. Pythagoras function for indirect height measurement. Memory storage for multiple measurements. Work in metres by default - convert to feet/inches in settings menu. Battery life: 3,000-5,000 measurements per charge.
Professional applications: Estate agents measure properties for floor plans (required for Energy Performance Certificates). Building surveyors measure structural defects for reports. Interior designers measure rooms for furniture placement. Carpet fitters calculate floor areas. Kitchen/bathroom installers verify dimensions against supplier plans. Landscapers measure gardens for material estimates. Construction site managers verify foundations against architect drawings.
Obsolete imperial units still referenced: Rod/pole/perch (5.5 yards = 5.03m) used in old land deeds and property boundaries. Chain (22 yards = 20.12m) - cricket pitch length, surveyors' chain for land measurement. Furlong (220 yards = 201.2m) - horse racing distances, still used at UK racecourses. Fathom (6 feet = 1.83m) - maritime depth measurement on old nautical charts. Hand (4 inches = 10.16cm) - horse height measurement (\"15 hands high\" = 60 inches = 152cm).
Historical context: Roman foot (296mm) influenced British foot before standardization. Saxon yard based on arm length (variable). Medieval building used body-based measurements - cubit (elbow to fingertip), span (thumb to little finger spread). Standardization began 1266 (Assize of Bread and Ale) but true uniformity only achieved 1824 (Weights and Measures Act) defining Imperial system. International Yard and Pound Agreement (1959) created current global standard.
| Measurement | UK Standard | EU Standard | US Standard |
|---|---|---|---|
| Road distances | Miles (mph) | Kilometres (km/h) | Miles (mph) |
| Personal height | Feet/inches (official: cm) | Centimetres | Feet/inches |
| Property area | Square feet (official: m²) | Square metres | Square feet |
| Construction | Millimetres (Building Regs) | Millimetres | Feet/inches |
| Screen sizes | Inches (packaging: cm) | Inches (packaging: cm) | Inches |
| Timber lumber | Metric lengths, imperial cross-sections | Millimetres | Feet/inches |
| Fuel consumption | Miles per gallon (mpg) | Litres per 100km | Miles per gallon (US gallon smaller than UK) |
Smartphone measurement apps: iPhone/iPad built-in Measure app uses AR (augmented reality) and LiDAR scanner (iPhone 12 Pro+) for distance/area measurement. Accuracy ±1-5% depending on lighting and surface. Android equivalents: Google Measure, AR Ruler. Useful for quick estimates but not professional accuracy. Works best under 5 metres range.
BIM and digital construction: Building Information Modeling (BIM) software (Autodesk Revit, ArchiCAD, Vectorworks) works natively in millimetres or feet-inches - user selectable. UK government mandates BIM Level 2 for public sector projects (infrastructure, schools, hospitals). Digital models contain precise measurements - contractors extract dimensions directly from 3D models, reducing measurement errors on site. Cloud-based collaboration allows real-time measurement verification.
GPS and geolocation accuracy: Consumer GPS (phone/car satnav) accurate to ±3-5 metres. Professional GPS (surveying grade) accurate to ±10mm using Real-Time Kinematic (RTK) correction. Ordnance Survey provides OS Net CORS (Continuously Operating Reference Stations) across UK for high-accuracy positioning. Used for land surveying, utility mapping, construction site control. Drones with RTK GPS map sites to cm-level accuracy.
UK universities and research institutions exclusively use SI units (International System of Units): metres, kilograms, seconds, amperes, kelvin, moles, candelas. GCSE/A-Level science exams require SI units - answers in imperial units marked wrong. Physics calculations use metres, chemistry uses nanometres/angstroms (atomic scale), biology uses micrometres (cell structures). Engineering degrees teach metric throughout - imperial only mentioned for legacy system maintenance.
Precision scales: Nanotechnology and materials science work at atomic scales: nanometre (10⁻⁹m), picometre (10⁻¹²m). Electron microscopes image structures smaller than wavelength of visible light. Atomic force microscopes (AFM) measure surface features at atomic resolution. Large Hadron Collider at CERN (UK participation) measures particle collision events at femtometre scale (10⁻¹⁵m). At opposite extreme, astronomy measures intergalactic distances in light-years and parsecs - UK observatories contribute to global catalogs.
Last updated: January 2026 | Verified with latest UK rates
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