MM → Inches

4 mm to inches

4 millimeters equals 0.15748 inches — or about 3/16" (nearest 1/16″).

Decimal

0.1575 in

Fraction

3/16"

Centimeters

0.4 cm

Feet

0.0131 ft

Millimeters (mm)

Inches (in)

0.15748

≈ 3/16" (nearest 1/16)

1 in = 25.4 mm · tolerance ±0.0001

Nearby values

3.9 mm 3.8 mm 4.2 mm 4.3 mm 3.6 mm 3.5 mm 4.5 mm 4.6 mm 3.4 mm 3.3 mm

Precision

0.1575

Inches

4.0 mm · max 100

Ref · 25.4 mm/in

Drag to set

Formula

To convert mm to inches, divide by 25.4:

inches = mm ÷ 25.4
inches = 4 ÷ 25.4 = 0.15748

Why 4 mm = 0.1575 in

Since 1 inch is defined as exactly 25.4 millimeters, 4 mm converts to 0.15748 inches. Rounded to the nearest 1/16″ that's 3/16", which is what you'd read off a standard imperial ruler.