MM → Inches
64 mm to inches
64 millimeters equals 2.519685 inches — or about 2 1/2" (nearest 1/16″).
Decimal
2.5197 in
Fraction
2 1/2"
Centimeters
6.4 cm
Feet
0.21 ft
mm
2.519685
in≈ 2 1/2" (nearest 1/16)
1 in = 25.4 mm · tolerance ±0.0001
Formula
To convert mm to inches, divide by 25.4:
inches = mm ÷ 25.4
inches = 64 ÷ 25.4 = 2.519685
Why 64 mm = 2.5197 in
Since 1 inch is defined as exactly 25.4 millimeters, 64 mm converts to 2.519685 inches. Rounded to the nearest 1/16″ that's 2 1/2", which is what you'd read off a standard imperial ruler.