MM → Inches
3.4 mm to inches
3.4 millimeters equals 0.133858 inches — or about 1/8" (nearest 1/16″).
Decimal
0.1339 in
Fraction
1/8"
Centimeters
0.34 cm
Feet
0.0112 ft
mm
0.133858
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 = 3.4 ÷ 25.4 = 0.133858
Why 3.4 mm = 0.1339 in
Since 1 inch is defined as exactly 25.4 millimeters, 3.4 mm converts to 0.133858 inches. Rounded to the nearest 1/16″ that's 1/8", which is what you'd read off a standard imperial ruler.