Length • NIST Exact

Centimeters Inches

cm → in

1 cm = 0.3937007874 inNIST Exact

cm → in Reference Table

cm in
0.01 cm 0.003937007874 in
0.1 cm 0.03937007874 in
0.5 cm 0.1968503937 in
1 cm 0.3937007874 in
2 cm 0.7874015748 in
5 cm 1.968503937 in
10 cm 3.937007874 in
20 cm 7.874015748 in
50 cm 19.68503937 in
100 cm 39.37007874 in
500 cm 196.8503937 in
1000 cm 393.7007874 in

Values based on NIST SP 811 conversion factors

🌍 Real-World Examples

Carry-on luggage max height (55 cm)

55 cm = 21.65354331 in

Carry-on luggage max width (40 cm)

40 cm = 15.7480315 in

Carry-on luggage max depth (20 cm)

20 cm = 7.874015748 in

Average adult height (170 cm)

170 cm = 66.92913386 in

Standard dining table height

80 cm = 31.49606299 in

Why Convert Centimeters to Inches?

Converting between centimeters (cm) and inches (in) is one of the most common length conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert cm to in saves time and prevents errors.

Length conversions between cm and in are essential in international travel, construction, and sports. Airline carry-on luggage limits are typically defined in centimeters (55×40×20 cm), but US travelers think in inches. Architects and contractors regularly convert between metric and imperial measurements when working on international projects. In athletics, track distances may be in meters while road races use miles or kilometers.

How to Convert Centimeters to Inches

To convert centimeters to inches, use the following formula:

in = cm × 0.3937007874

Example: 1 cm = 0.3937007874 in

For example, 5 cm = 1.968503937 in, 10 cm = 3.937007874 in, and 100 cm = 39.37007874 in. Our calculator above performs this conversion instantly with full precision — no rounding errors.

Common Use Cases

  • Carry-on luggage max height (55 cm): 55 cm = 21.65354331 in
  • Carry-on luggage max width (40 cm): 40 cm = 15.7480315 in
  • Carry-on luggage max depth (20 cm): 20 cm = 7.874015748 in
  • Average adult height (170 cm): 170 cm = 66.92913386 in
  • Standard dining table height: 80 cm = 31.49606299 in

Common Mistakes to Avoid

  • Confusing similar units: Don't mix up meters (m) with miles (mi) — they differ by a factor of ~1600. Always check the unit symbol.
  • Rounding too early: When converting cm to in, carry at least 4 decimal places in intermediate calculations to avoid compounding errors.
  • Forgetting unit labels: Always write the unit symbol after the number. "5.5" is ambiguous — "5.5 in" is clear.

Pro Tips

  • Memorize the factor: 1 cm = 0.3937007874 in. For quick mental math, remember this base conversion.
  • Quick reference: 5 cm = 1.968503937 in · 10 cm = 3.937007874 in · 25 cm = 9.842519685 in · 50 cm = 19.68503937 in · 100 cm = 39.37007874 in
  • Bookmark this page: Save this converter for instant access. It works offline once loaded — no internet needed.

Centimeters to Inches Conversion Table

cmin
0.01 cm0.003937007874 in
0.1 cm0.03937007874 in
0.5 cm0.1968503937 in
1 cm0.3937007874 in
2 cm0.7874015748 in
5 cm1.968503937 in
10 cm3.937007874 in
20 cm7.874015748 in
50 cm19.68503937 in
100 cm39.37007874 in
500 cm196.8503937 in
1000 cm393.7007874 in

All values in this table are mathematically exact per NIST SP 811.

Frequently Asked Questions

How many inches are in 1 centimeter?

1 cm equals 0.3937007874 in. This is an exact conversion factor defined by NIST.

How do I convert centimeters to inches?

Multiply the value in cm by the conversion factor. For example, 10 cm = 3.937007874 in. Use our calculator above for instant results.

Is the centimeters to inches conversion exact?

Yes, this conversion is mathematically exact based on the international definition of these units (NIST SP 811).

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