How to use
- Type the decimal, for example 0.625 or 2.5. For a repeating decimal, put the repeating digits in parentheses: 0.(142857).
- Pick a tolerance if the decimal was rounded; the default finds 1/3 from 0.333333.
- Read the fraction, mixed number and percent.
Worked example: 0.4375 and 0.1(6)
0.4375 is exactly 4375/10000. Dividing numerator and denominator by their greatest common divisor 625 gives 7/16.
0.1(6) means 0.1666… which is exactly 1/6. Typed as a rounded 0.1667, the continued-fraction search still returns 1/6 at the default tolerance.
Frequently asked questions
How is a terminating decimal converted?
Write it over a power of ten and simplify by the greatest common divisor: 0.625 = 625/1000 = 5/8.
How do I enter a repeating decimal?
Put the repeating block in parentheses: 0.(3) for 0.333…, 0.1(6) for 0.1666…, 0.(142857) for 1/7.
What does tolerance do?
A rounded decimal like 0.333333 is not exactly 1/3. The search returns the simplest fraction within the tolerance, so a looser tolerance gives simpler fractions.
Why 1/16 tolerance?
Useful for measurements: 0.3 inch becomes 5/16 at that setting, matching a ruler.
Can it convert negative decimals?
Yes: −0.75 becomes −3/4.
How is a decimal over 1 shown?
Both ways: 2.5 is 5/2 improper and 2 1/2 mixed.