MM → Inches
3 mm to inches
3 millimeters equals 0.11811 inches — or about 1/8" (nearest 1/16″).
Decimal
0.1181 in
Fraction
1/8"
Centimeters
0.3 cm
Feet
0.0098 ft
mm
0.11811
in≈ 1/8" (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 = 3 ÷ 25.4 = 0.11811
Why 3 mm = 0.1181 in
Since 1 inch is defined as exactly 25.4 millimeters, 3 mm converts to 0.11811 inches. Rounded to the nearest 1/16″ that's 1/8", which is what you'd read off a standard imperial ruler.