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1/8 inch to decimal

The exact decimal value of 1/8 of an inch, with millimetres, centimetres and decimal feet — the numbers a tape or a caliper actually shows.

1/8 inch =

=0.125 in

Decimal inch

0.125"

Millimetres

3.175 mm

Centimetres

0.3175 cm

Decimal feet

0.010417 ft

How it's figured

1 ÷ 8

A fraction of an inch is just the top number divided by the bottom: 1 ÷ 8 = 0.125". For metric, one inch is exactly 25.4 mm, so 0.125" × 25.4 = 3.175 mm. TapeMath keeps this exact as a fraction internally, so it never drifts the way a rounded decimal can.

Fractions nearby

The steps around 1/8"

Fraction	Decimal inch	Millimetres
5/64"	0.078125	1.984375 mm
3/32"	0.09375	2.38125 mm
7/64"	0.109375	2.778125 mm
1/8"	0.125	3.175 mm
9/64"	0.140625	3.571875 mm
5/32"	0.15625	3.96875 mm
11/64"	0.171875	4.365625 mm

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