MM → Inches
9.75 mm to inches
9.75 millimeters equals 0.383858 inches — or about 3/8" (nearest 1/16″).
Decimal
0.3839 in
Fraction
3/8"
Centimeters
0.975 cm
Feet
0.032 ft
mm
0.383858
in≈ 3/8" (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 = 9.75 ÷ 25.4 = 0.383858
Why 9.75 mm = 0.3839 in
Since 1 inch is defined as exactly 25.4 millimeters, 9.75 mm converts to 0.383858 inches. Rounded to the nearest 1/16″ that's 3/8", which is what you'd read off a standard imperial ruler.