length · in
Inch (in)
An inch (in) is a length unit in the imperial and US customary systems. Exactly 1 inch = 25.4 millimeters = 2.54 centimeters.
Definition
An inch (in) is a length unit in the imperial and US customary systems. Exactly 1 inch = 25.4 millimeters = 2.54 centimeters.
History & origin
The word inch comes from Latin uncia (“one-twelfth”). Since 1959, the international inch has been fixed at exactly 25.4 mm by agreement among English-speaking countries.
Conversion formula
cm = inch × 2.54 · inch = cm ÷ 2.54 · 12 inches = 1 foot
Frequently asked questions
- How many cm is 1 inch?
- Exactly 2.54 cm. Example: 10 inches = 25.4 cm.
- Is an inch the same worldwide?
- Yes for modern science and trade: the international inch is 25.4 mm. Older survey inches in some contexts differ slightly.
- How do I convert inches to feet?
- Divide by 12. Example: 36 inches = 3 feet.
Related units
💡 Try converting Inch now
/convert/inch-to-cm →