What is 0.5 as a fraction?

0.5 as a fraction is 1/2. Write the digits over 10 to get 5/10, then divide top and bottom by 5.

What is 0.5 as a percentage?

0.5 is 50%. Multiplying a decimal by 100 moves the point two places to the right.

How many millimetres is 0.5 of an inch?

0.5 inches is 12.7 mm, using the exact definition 1 inch = 25.4 mm.

0.5 as a fraction

Fraction1/2lowest terms

Decimal0.5

Percent50%

How to get there

0.5 has 1 digit after the point, so it is that many tenths: write the digits over 10 — 5/10.
5 and 10 share a greatest common divisor of 5. Divide both by it: 1/2.

50 of 100 squares — 0.5 of the whole, which is also 50%.

As a measurement

Read as inches, 0.5″ is 12.7 mm exactly. The nearest marks on a rule:

Rule	Nearest mark	Inches	mm	Difference
16ths	1/2″	0.5	12.7	exact
32ths	1/2″	0.5	12.7	exact
64ths	1/2″	0.5	12.7	exact

Common questions

What is 0.5 as a fraction?: 0.5 as a fraction is 1/2. Write the digits over 10 to get 5/10, then divide top and bottom by 5.
What is 0.5 as a percentage?: 0.5 is 50%. Multiplying a decimal by 100 moves the point two places to the right.
How many millimetres is 0.5 of an inch?: 0.5 inches is 12.7 mm, using the exact definition 1 inch = 25.4 mm.

The same number, other ways

1/2Everything about the fraction: equivalents, the bar model, the number line.50%The same value as a percentage, with its own derivation.Decimal → fraction chartThe whole lookup table, printable.Nearest fractionMatch 0.5″ against any rule, with the exact error.

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.