Convert centimeters to inches and vice versa instantly. Perfect for height, screen sizes, and measurements. Includes fraction converter.
Inches = Centimeters ÷ 2.54
Example: 100 cm ÷ 2.54 = 39.37 inches
Centimeters = Inches × 2.54
Example: 10 inches × 2.54 = 25.4 cm
1. Learn common height conversions by heart: UK passports/licenses use cm, but most Brits think in feet/inches. Memorise your height in both: 5'9\" = 175 cm, 5'10\" = 178 cm, 6'0\" = 183 cm, 5'4\" = 163 cm (average UK woman), 5'6\" = 168 cm, 5'8\" = 173 cm. Medical forms, gym memberships, and ID documents all ask for height in cm.
2. TV and monitor shopping strategy: UK retailers advertise screen sizes in inches (55\", 65\", 27\"), but you need to measure your wall space in cm/metres. Convert your available width: a 55\" TV is 121.76 cm wide (16:9 aspect). Add 5-10 cm clearance each side. A 150 cm wall fits a 55\" TV comfortably. Samsung/LG websites often show both measurements.
3. Clothing sizes - waist measurements: Jeans and trousers in the UK use inches for waist (28\", 30\", 32\", 34\", 36\"), but European sizes use cm. A 32\" waist = 81 cm (EU size 42). Men's shirts use inches for collar (15\", 15.5\", 16\", 16.5\", 17\") and sleeve length. Always measure yourself in cm with a tape measure, then convert to find your size.
4. DIY and construction conversions: UK building materials straddle both systems. Plasterboard: 8ft × 4ft sheets (244 cm × 122 cm). Timber: sold in metric lengths (2.4m, 3.0m) but thickness/width in mm or inches. A \"2×4\" stud is actually 38mm × 89mm (not 2\" × 4\" exactly). Door widths: 30\" (762 mm) or 32\" (813 mm) are standard UK internal door sizes.
5. Use fractions for precision work: Carpentry, tailoring, and engineering often need fractional inches: 1/8\" = 3.175 mm, 1/4\" = 6.35 mm, 1/2\" = 12.7 mm. British craftsmen traditionally used 1/16\" increments. Modern UK drill bits come in metric (6mm, 8mm, 10mm) but American tools use fractions. This converter shows both decimals and fractions.
6. Phone and laptop screen sizes: All smartphones and laptops worldwide are sold with inch measurements (6.1\", 6.7\", 13.3\", 15.6\"), but packaging must also show cm in UK/EU. iPhone 15: 6.1\" = 15.49 cm diagonal. MacBook Air: 13.6\" = 34.54 cm. These are diagonal measurements corner-to-corner, not width/height.
7. International furniture shopping: IKEA and online retailers list dimensions in cm (120cm wide), but UK property listings often describe rooms in feet (12ft × 10ft = 3.66m × 3.05m). Measure your room in metres with a laser measure, convert to cm, then check if furniture fits. A 200 cm (78.7\") sofa fits easily in a 4-metre-wide room.
8. Healthcare and body measurements: NHS uses cm/metres for height, kg for weight. Baby growth charts use cm. However, older UK adults often report height in feet/inches to doctors who record it in cm. BMI calculators need consistent units - either all metric (cm, kg) or all imperial (inches, lbs). Don't mix units.
9. Quick mental approximations: For rough estimates without a calculator: 1 inch ≈ 2.5 cm (slightly less), 10 cm ≈ 4 inches (slightly less), 30 cm ≈ 1 foot (slightly less), 1 metre ≈ 3.3 feet. Example: 50 inches × 2.5 = 125 cm (actual: 127 cm) - close enough for quick furniture checks in shops.
Mistake 1: Rounding too early in calculations. Don't round until the final answer. If converting 175.26 cm to feet, don't round to 175 cm first (gives 5.74 ft) - you lose accuracy. Calculate 175.26 cm ÷ 2.54 = 68.999 inches ÷ 12 = 5.75 feet (5'9\"), then round to 5'9\" (not 5'8\"). Small rounding errors accumulate in multi-step conversions.
Mistake 2: Using 2.5 instead of 2.54. 1 inch = 2.54 cm exactly, not 2.5. This 1.6% error seems small but compounds: 100 inches × 2.5 = 250 cm (wrong). Actual: 100 × 2.54 = 254 cm. For a 6-foot person (72 inches), using 2.5 gives 180 cm (wrong), actual is 182.88 cm. UK building regulations require exact conversions - approximations can fail inspections.
Mistake 3: Confusing decimal inches with feet/inches. 5.9 feet ≠ 5'9\". 5.9 feet = 5 feet + 0.9 feet = 5 feet + (0.9 × 12) inches = 5'10.8\". Always convert the decimal part: 0.9 feet × 12 = 10.8 inches. Many online converters show 5.9 ft without clarifying this isn't 5'9\". 5'9\" = 5.75 feet decimal (9 ÷ 12 = 0.75).
Mistake 4: Mixing up cm and mm. UK construction uses mm for precision (plasterboard thickness: 12.5mm), but everyday measurements use cm. 1cm = 10mm. A 15.6\" laptop screen = 39.62 cm = 396.2 mm. When reading architect drawings (always in mm), divide by 10 for cm: 2400mm = 240 cm = 7.87 feet. Double-check which unit you're converting from/to.
Mistake 5: Forgetting UK nominal vs actual sizes. A UK \"2×4\" piece of timber isn't 2 inches × 4 inches - it's 38mm × 89mm (1.5\" × 3.5\" actual). These are nominal sizes from before planing. Similarly, a 4×2 metre sheet of plywood is actually 2440mm × 1220mm (8ft × 4ft, slightly oversized). Always check actual dimensions, not labels.
Mistake 6: Not accounting for diagonal measurements. TV/monitor sizes are diagonal, not width. A 55\" TV is not 55 inches wide - it's 47.9\" wide × 27\" tall (121.7 cm × 68.6 cm) for 16:9 aspect ratio. Calculate width: diagonal × 0.87 for 16:9 screens. A 32\" monitor ≈ 27.8\" (70.6 cm) wide. Measure your desk/wall, not just the advertised diagonal size.
Mistake 7: Using wrong conversion for square measurements. Square cm to square inches is NOT ÷ 2.54. It's ÷ 6.4516 (2.54²). Example: 100 cm² = 100 ÷ 6.4516 = 15.5 in², not 39.4 in². For square metres to square feet: × 10.764, not × 3.28. Area conversions are different from length conversions - the conversion factor is squared.
Mistake 8: Ignoring international inch variations. Before 1959, UK and US inches differed. Old UK buildings may have been designed using the Imperial inch (25.4000508 mm, 0.0002% larger than today's 25.4 mm exactly). This matters for heritage building restoration and antique furniture. Modern conversions always use 2.54 cm/inch, but pre-1959 drawings may need historical conversion factors.
The United Kingdom has a unique dual measurement system that uses both metric (centimetres, metres) and imperial (inches, feet) measurements in daily life. While the UK officially adopted the metric system in 1965 and completed metrication of most sectors by 1995, imperial units remain legal and widely used in specific contexts.
Why this happened: The Weights and Measures Act 1985 made metric units the primary system for trade, but carved out exceptions. The EU Directive 80/181/EEC required metric-first labeling but allowed supplementary imperial units. Post-Brexit, the UK is reviewing these rules, but the dual system is so embedded in British culture that major change is unlikely. Most Brits under 40 think in metric for science/DIY, but imperial for height, weight, and distances.
Before 1959, the UK, USA, Canada, Australia, New Zealand, and South Africa all had slightly different definitions of the inch. The British Imperial inch was defined as 2.53998 cm, while the US inch was 2.540005 cm - a tiny difference, but significant for precision engineering and international trade.
On July 1, 1959, these countries signed the International Yard and Pound Agreement, defining 1 inch = 2.54 centimetres exactly, and 1 yard = 0.9144 metres exactly. This unified the English-speaking world's measurements and is the conversion factor used globally today. The UK adopted this immediately, though some survey measurements continued using the old Imperial inch until the 1960s.
| Scenario | Units Used | Conversion Example |
|---|---|---|
| Buying a TV | Inches (screen) vs cm (wall space) | 55\" TV = 121.76 cm wide. Need 140+ cm wall space. |
| Passport application | Height in cm required | 5'10\" person enters 178 cm on form. |
| Buying jeans | Waist in inches, measure yourself in cm | Waist measures 86 cm = 33.86\", buy 34\" jeans. |
| DIY timber purchase | Length in metres, cross-section in mm | Need 8 feet of 2×4: buy 2.4m length of 38×89mm stud. |
| Reading US recipe | Recipe in inches, UK oven in cm | 9-inch cake tin = 23 cm cake tin (round up to 24 cm). |
| Ordering online from EU | EU furniture in cm, UK room in feet | 12ft × 10ft room = 366 cm × 305 cm. 200 cm sofa fits comfortably. |
| Gym height/weight check | Height in cm, weight in kg | 5'9\" = 175 cm. 12 stone = 76.2 kg. (Both conversions needed!) |
| Hanging a picture frame | Frame in inches, wall markings in cm | 16\"×20\" frame = 40.64 × 50.8 cm. Mark wall at 40 cm and 50 cm for drill holes. |
Traditional UK craftsmanship uses fractional inches (1/2\", 1/4\", 1/8\", 1/16\") rather than decimal inches. A measurement of 5.75 inches would be written as 5 3/4 inches. Modern digital tools show decimals, but rulers, tape measures, and workshop tools often have fractional markings.
Common fractions and their decimal/metric equivalents:
1/16\" = 0.0625\" = 1.588 mm
1/8\" = 0.125\" = 3.175 mm
1/4\" = 0.25\" = 6.35 mm
3/8\" = 0.375\" = 9.525 mm
1/2\" = 0.5\" = 12.7 mm
5/8\" = 0.625\" = 15.875 mm
3/4\" = 0.75\" = 19.05 mm
7/8\" = 0.875\" = 22.225 mm
1\" = 1.0\" = 25.4 mm
Automotive: Metric bolts and fasteners (M6, M8, M10, M12) dominate, but wheel sizes, tyre diameters, and some classic car parts use inches. Torque settings given in Nm (newton-metres) not lb-ft. Fuel consumption: mpg (miles per gallon) still used despite fuel sold in litres.
Printing and graphic design: Global standard is points (pt) and picas, not cm or inches. However, paper sizes are ISO A-series (A4 = 210 × 297 mm). Older UK printers may reference imperial sizes: Letter (8.5\" × 11\"), Legal (8.5\" × 14\").
Aviation: Altitude in feet, visibility in metres, runway lengths in metres, but aircraft dimensions often in feet. This mixed system is international standard (ICAO). Flight levels: FL350 = 35,000 feet altitude.
Shipping and maritime: Depths in fathoms (6 feet) or metres depending on chart age. Container sizes in feet (20ft, 40ft containers). Nautical miles for distance (1 nm = 1.852 km), but speeds in knots.
To convert centimeters to inches, divide the cm value by 2.54. For example, 50 cm ÷ 2.54 = 19.69 inches.
To convert inches to centimeters, multiply the inch value by 2.54. For example, 10 inches × 2.54 = 25.4 cm.
The inch is officially defined as exactly 2.54 centimeters. This is an international standard set in 1959.
This converter uses the official conversion factor of 2.54 and provides results accurate to 2 decimal places.
Yes! This tool is perfect for converting height measurements between cm and inches/feet.
Last updated: January 2026 | Verified with latest UK rates