Is 2.54 exact?
Yes. The inch has been defined as exactly 2.54 cm since the 1959 international yard and pound agreement, so the conversion involves no rounding.
Convert centimeters to inches and inches to centimeters instantly. Includes a quick reference table for common conversions.
Inches = cm ÷ 2.54. Centimetres = inches × 2.54. Feet and inches: total inches ÷ 12 for feet, remainder as inches.
170 cm ÷ 2.54 = 66.93 in, which is 5 ft 6.9 in. Going the other way, 12 in × 2.54 = 30.48 cm.
Yes. The inch has been defined as exactly 2.54 cm since the 1959 international yard and pound agreement, so the conversion involves no rounding.
Convert to total inches first, then divide by 12. The whole number is feet and the remainder is inches — 180 cm is 70.87 in, or 5 ft 10.9 in.
Divide centimetres by 2.5 and subtract a little. 100 cm ≈ 40 in estimated, versus 39.4 in actual — close enough for rough sizing.