⚖️ Comparison · Updated for 2026
Centimetres vs Inches
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
Quick answer: 1 inch = 2.54 cm exactly. The factor has been internationally agreed since 1959. Centimetres are SI-standard; inches dominate in the US, UK (for short distances) and aviation worldwide.
Decision guide — when to use which
Use Centimetres when…
All scientific work, most of the world for everyday measurements, screen sizes in some markets.
Use Inches when…
US construction, US sewing, UK building trade, screen sizes (TV/monitor diagonals), pipe and bolt sizes worldwide.
📊 Side-by-side comparison
| Aspect | Centimetres | Inches |
|---|---|---|
| Definition | SI: 1/100 of a metre | Exactly 25.4 mm by international agreement |
| Symbol | cm | in or " |
| Common precision | mm (1/10 cm) | 1/16 inch or 1/32 inch in trades |
| Body height | Used in most countries | UK and US default for personal height |
Frequently asked
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Is 1 inch exactly 2.54 cm?
Yes, exactly. Since 1959, the international inch has been defined as 25.4 mm by treaty.
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What's 6 foot in cm?
6 feet = 72 inches = 182.88 cm, universally rounded to 183 cm in clinical records. Common heights: 5'6" = 167.6 cm, 5'8" = 172.7 cm, 5'10" = 177.8 cm, 6'0" = 182.9 cm, 6'2" = 187.9 cm. The UK uses cm for medical records, but feet/inches in everyday conversation.
Reviewed for 2026. All conversion factors and historical references verified against official sources (ISO standards, government weights & measures legislation, IEC technical specifications). Built by a UK-based qualified primary teacher and FA Level 2 coach as part of 247QuickTools' free utility-tools project. We don't sell SEO links or accept paid placements in this content.