MM → Inches
30.5 mm to inches
30.5 millimeters equals 1.200787 inches — or about 1 3/16" (nearest 1/16″).
Decimal
1.2008 in
Fraction
1 3/16"
Centimeters
3.05 cm
Feet
0.1001 ft
mm
1.200787
in≈ 1 3/16" (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 = 30.5 ÷ 25.4 = 1.200787
Why 30.5 mm = 1.2008 in
Since 1 inch is defined as exactly 25.4 millimeters, 30.5 mm converts to 1.200787 inches. Rounded to the nearest 1/16″ that's 1 3/16", which is what you'd read off a standard imperial ruler.