The Formula
inches = cm ÷ 2.54
The inch has been defined as exactly 2.54 cm since 1959, so this conversion is exact, never approximate. The example above: 170 cm ÷ 2.54 = 66.93 in — which is 5 feet 6.9 inches, a common human height.
Reading the Result as Feet and Inches
Heights in the US are spoken in feet + inches, so divide the inch result by 12: 66.93 in = 5 ft + 6.93 in ≈ 5′7″. Handy anchors: 160 cm = 5′3″, 170 cm = 5′7″, 175 cm = 5′9″, 180 cm = 5′11″, 185 cm = 6′1″, 190 cm = 6′3″. Between anchors, each 2.5 cm ≈ 1 inch.
Where This Conversion Shows Up
Height on forms, dating profiles, and sports rosters. Screens and TVs are sold in inches everywhere — but note screen sizes measure the diagonal, so a “55-inch” TV is 140 cm corner to corner, not wide. Sewing and DIY plans from US sources arrive in inches with fractions: 1/8 in = 0.32 cm, 1/4 in = 0.64 cm, 1/2 in = 1.27 cm. Paper: the US Letter format is 8.5 × 11 in = 21.6 × 27.9 cm, slightly wider and shorter than A4 (21 × 29.7 cm).
Frequently Asked Questions
How many inches is 1 cm?
0.3937 in — a centimeter is a bit less than 4/10 of an inch. Going the other way is cleaner: 1 inch is exactly 2.54 cm.
What is 170 cm in feet and inches?
5 feet 6.9 inches — rounded to 5′7″ in everyday use. See the anchors above for the surrounding heights.
Why 2.54 exactly?
The 1959 international yard and pound agreement defined the yard as exactly 0.9144 m, making the inch exactly 25.4 mm. Before that, the US and UK inches differed by millionths — a real problem for precision engineering.
How do I convert to inch fractions like 3/8?
Convert to decimal inches here, then multiply the fractional part by the denominator you need: 0.375 in × 8 = 3, so 3/8 in. Rulers use eighths and sixteenths; 1 cm ≈ 13/32 in in sixteenth-precision work.