What is 1/10 as a decimal?

1/10 is exactly 0.1 as a decimal.

How many millimetres is 1/10 of an inch?

1/10 of an inch is 2.54 mm, computed with the exact definition 1 inch = 25.4 mm.

1/10

Fraction1/10

Decimal0.1

Percent10%

1 of 10 equal parts filled — the same share as a bar and as a circle.

Where the decimal comes from

1/10 equals 0.1.

The denominator is already a power of ten, and that is what a decimal is: 0.1 means 1 tenths.

10 of 100 squares — 0.1 of the whole. The same squares read as a percentage: 10%, because percent means per hundred.

Every way to write it

Decimal: 0.1
Percent: 10%
Ratio: 1 : 10 (part to whole)
As inches: 1/10″ = 2.54 mm

Equivalent fractions

Multiply the top and bottom of 1/10 by the same number and the value does not change:

1/10 = 2/20 = 3/30 = 4/40 = 5/50 = 6/60 · more, or pick a denominator

On the number line

As a measurement

Read as inches, 1/10″ is 2.54 mm exactly. The nearest marks on the finer rules:

Rule	Nearest mark	Decimal inches	mm	Difference
16ths	1/8″	0.125	3.175	+0.635 mm
32ths	3/32″	0.09375	2.3813	−0.1588 mm
64ths	3/32″	0.09375	2.3813	−0.1588 mm

Need a different rule or a tolerance? Nearest fraction · Within tolerance

Common questions

What is 1/10 as a decimal?: 1/10 is exactly 0.1 as a decimal.
What is 1/10 as a percentage?: 1/10 is exactly 10%.
How many millimetres is 1/10 of an inch?: 1/10 of an inch is 2.54 mm, computed with the exact definition 1 inch = 25.4 mm.

Fraction–decimal chartThe everyday set, printable.Rule charts16ths, 32nds, 64ths, 128ths.The rulerSee 1/10 in its place.

Where this comes from. Exact rational arithmetic on the values shown — fractions are pairs of integers until display, and inch–metric conversion uses 25.4 mm to the inch, exact by definition since 1959. See the full methodology.