MM → Inches
80 mm to inches
80 millimeters equals 3.149606 inches — or about 3 1/8" (nearest 1/16″).
Decimal
3.1496 in
Fraction
3 1/8"
Centimeters
8 cm
Feet
0.2625 ft
mm
3.149606
in≈ 3 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 = 80 ÷ 25.4 = 3.149606
Why 80 mm = 3.1496 in
Since 1 inch is defined as exactly 25.4 millimeters, 80 mm converts to 3.149606 inches. Rounded to the nearest 1/16″ that's 3 1/8", which is what you'd read off a standard imperial ruler.