MM → Inches

13 mm to inches

13 millimeters equals 0.511811 inches — or about 1/2" (nearest 1/16″).

Decimal

0.5118 in

Fraction

1/2"

Centimeters

1.3 cm

Feet

0.0427 ft

mm
0.511811
in

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 = 13 ÷ 25.4 = 0.511811

Why 13 mm = 0.5118 in

Since 1 inch is defined as exactly 25.4 millimeters, 13 mm converts to 0.511811 inches. Rounded to the nearest 1/16″ that's 1/2", which is what you'd read off a standard imperial ruler.