Inches to Centimetres: The Complete Guide
Inches to centimetres is one of the most needed conversions for people working across metric and imperial systems — height in medical records, screen sizes, clothing measurements, and woodworking all require it regularly.
The Conversion Formula
centimetres = inches × 2.54Since 1 inch = 2.54 cm exactly, this conversion is always precise.
Quick Reference Table
- 1 in = 2.54 cm
- 6 in = 15.24 cm
- 12 in (1 ft) = 30.48 cm
- 24 in = 60.96 cm
- 36 in (1 yd) = 91.44 cm
- 72 in (6 ft) = 182.88 cm
Common Use Cases
- Height records: US driving licences and medical records use feet/inches; most of the world uses cm
- Screen sizes: A 55-inch TV has a diagonal of 139.7 cm
- Clothing: Converting waist size 32" to 81 cm for European sizing
- DIY and carpentry: Working from US plans when using metric tools
Convert any length instantly: Free inches to cm converter
Complete Reference Table
- 6 in = 15.24 cm
- 12 in (1 ft) = 30.48 cm
- 18 in = 45.72 cm
- 24 in (2 ft) = 60.96 cm
- 36 in (1 yd) = 91.44 cm
- 48 in (4 ft) = 121.92 cm
- 60 in (5 ft) = 152.40 cm
- 72 in (6 ft) = 182.88 cm
Real-World Applications
The inches-to-centimetres conversion arises constantly when people move between countries or work with international specifications. Common situations include: recording height in a medical clinic abroad (a 5 ft 9 in person is 175.26 cm), buying clothing online from international retailers whose size charts use cm, reading screen and monitor dimensions (a 27-inch monitor diagonal equals 68.58 cm), and measuring timber or fabric sold in imperial lengths for projects using metric plans. Interior designers frequently convert room dimensions from architectural drawings (in inches) to centimetre measurements for ordering furniture from European suppliers.
Common Mistakes
- Rounding 2.54 to 2.5: Using 2.5 instead of the exact factor 2.54 introduces a 1.6% error — on a 6-foot measurement that is a 2.9 cm discrepancy, enough to matter in construction or tailoring.
- Confusing cm with mm: Centimetres and millimetres are often mixed up. Remember: 1 cm = 10 mm. If a result looks ten times too large, you have likely read millimetres.
- Forgetting feet + inches: Heights like 5 ft 9 in must be fully converted. First convert 5 ft to 60 in, then add 9 in to get 69 in total, then multiply by 2.54 = 175.26 cm.
Frequently Asked Questions
Is the conversion factor exactly 2.54?
Yes. Since 1959, one international inch has been defined as exactly 2.54 centimetres. This is not an approximation — it is an exact legal definition adopted by the United States, United Kingdom, Canada, Australia, and South Africa. All inch-to-centimetre conversions are therefore exact to as many decimal places as you need.
How do I convert fractional inches like 1/4 or 3/8 inch?
Convert the fraction to a decimal first, then multiply by 2.54. For example, 3/8 inch = 0.375 inches × 2.54 = 0.9525 cm. Common fractions: 1/4 in = 0.635 cm, 1/2 in = 1.27 cm, 3/4 in = 1.905 cm, 1/8 in = 0.3175 cm.
Which countries still use inches primarily?
The United States uses inches for everyday measurements such as height, room dimensions, and clothing. The United Kingdom uses a mix — road distances in miles, personal heights often in feet and inches, but official scientific and engineering measurements in SI metric units. Most other countries use centimetres exclusively.