MM → Inches
15.9 mm to inches
15.9 millimeters equals 0.625984 inches — or about 5/8" (nearest 1/16″).
Decimal
0.626 in
Fraction
5/8"
Centimeters
1.59 cm
Feet
0.0522 ft
mm
0.625984
in≈ 5/8" (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 = 15.9 ÷ 25.4 = 0.625984
Why 15.9 mm = 0.626 in
Since 1 inch is defined as exactly 25.4 millimeters, 15.9 mm converts to 0.625984 inches. Rounded to the nearest 1/16″ that's 5/8", which is what you'd read off a standard imperial ruler.