How this works
1 cm = 0.3937 inches. The factor comes from the international yard-and-pound agreement of 1959, which fixed 1 inch as exactly 2.54 cm — making the cm-to-inches conversion the reciprocal: 1 / 2.54 ≈ 0.3937. Type a centimetre value into the calculator above and the converter shows inches plus every other common length unit.
The formula
Use ÷ 2.54 for the exact answer; × 0.4 gets you a rough mental estimate (off by about 1.6%). For body height, divide cm by 2.54 then break the result into feet (every 12 inches) and remaining inches — e.g. 178 cm ÷ 2.54 = 70.08 in = 5 ft 10.08 in.
Example calculation
- 1 cm = 0.3937 in
- 10 cm = 3.937 in
- 30 cm = 11.81 in (≈ a school ruler)
- 178 cm = 70.08 in (≈ 5 ft 10 in)
Frequently asked questions
Is 1 inch exactly 2.54 cm?
Yes — exactly. Since 1959, the international inch is defined as 2.54 cm by treaty, which means cm-to-inch and inch-to-cm conversions have no rounding at the source. The 0.3937 figure for cm-to-inches is the reciprocal (1 / 2.54), which itself is irrational in decimal — that's why you see "≈" on most lookup tables.
How tall am I in feet and inches if I'm 175 cm?
175 ÷ 2.54 = 68.90 inches. Divide by 12 to get feet: 68.90 / 12 = 5 feet remainder 8.90 inches → 5 ft 8.90 in (commonly rounded to 5' 9"). The pattern: divide cm by 2.54 for total inches, then split into feet (every 12) and remaining inches.