What is 0.45 as a fraction?

0.45 as a fraction is 9/20. Write the digits over 100 to get 45/100, then divide top and bottom by 5.

What is 0.45 as a percentage?

0.45 is 45%. Multiplying a decimal by 100 moves the point two places to the right.

How many millimetres is 0.45 of an inch?

0.45 inches is 11.43 mm, using the exact definition 1 inch = 25.4 mm.

0.45 as a fraction

Fraction9/20lowest terms

Decimal0.45

Percent45%

How to get there

0.45 has 2 digits after the point, so it is that many hundredths: write the digits over 100 — 45/100.
45 and 100 share a greatest common divisor of 5. Divide both by it: 9/20.

45 of 100 squares — 0.45 of the whole, which is also 45%.

As a measurement

Read as inches, 0.45″ is 11.43 mm exactly. The nearest marks on a rule:

Rule	Nearest mark	Inches	mm	Difference
16ths	7/16″	0.4375	11.1125	−0.3175 mm
32ths	7/16″	0.4375	11.1125	−0.3175 mm
64ths	29/64″	0.453125	11.5094	+0.0794 mm

Common questions

What is 0.45 as a fraction?: 0.45 as a fraction is 9/20. Write the digits over 100 to get 45/100, then divide top and bottom by 5.
What is 0.45 as a percentage?: 0.45 is 45%. Multiplying a decimal by 100 moves the point two places to the right.
How many millimetres is 0.45 of an inch?: 0.45 inches is 11.43 mm, using the exact definition 1 inch = 25.4 mm.

The same number, other ways

9/20Everything about the fraction: equivalents, the bar model, the number line.45%The same value as a percentage, with its own derivation.Decimal → fraction chartThe whole lookup table, printable.Nearest fractionMatch 0.45″ 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.