What is 1/4 as a decimal?

1/4 is exactly 0.25 as a decimal.

How many millimetres is 1/4 of an inch?

1/4 of an inch is 6.35 mm, computed with the exact definition 1 inch = 25.4 mm.

1/4

Fraction1/4

Decimal0.25

Percent25%

1 of 4 equal parts filled — the same share as a bar and as a circle.

Where the decimal comes from

1/4 equals 25/100 equals 0.25.

Multiply the top and bottom by 25 and the denominator becomes 100. A fraction over 100 is what a decimal is: 0.25 means 25 hundredths.

25 of 100 squares — 0.25 of the whole. The same squares read as a percentage: 25%, because percent means per hundred.

Every way to write it

Decimal: 0.25
Percent: 25%
Ratio: 1 : 4 (part to whole)
As inches: 1/4″ = 6.35 mm

Equivalent fractions

Multiply the top and bottom of 1/4 by the same number and the value does not change:

1/4 = 2/8 = 3/12 = 4/16 = 5/20 = 6/24 · more, or pick a denominator

On the number line

As a measurement

Read as inches, 1/4″ is 6.35 mm exactly. The nearest marks on the finer rules:

Rule	Nearest mark	Decimal inches	mm	Difference
16ths	1/4″	0.25	6.35	exact
32ths	1/4″	0.25	6.35	exact
64ths	1/4″	0.25	6.35	exact

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

Common questions

What is 1/4 as a decimal?: 1/4 is exactly 0.25 as a decimal.
What is 1/4 as a percentage?: 1/4 is exactly 25%.
How many millimetres is 1/4 of an inch?: 1/4 of an inch is 6.35 mm, computed with the exact definition 1 inch = 25.4 mm.

Fraction–decimal chartThe everyday set, printable.Rule charts16ths, 32nds, 64ths, 128ths.The rulerSee 1/4 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.

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