How to convert a decimal to a fraction
Write the decimal digits over the matching power of 10, then simplify Example: 0.8 = 8/10 = 4/5 (simplified) This calculator converts the exact decimal you type, digit for digit. Typing "0.333" produces exactly 333/1000, not 1/3 — even though 1/3 rounds to 0.333, the two aren't the same number, and guessing that you meant the repeating decimal would mean silently changing what you actually typed. If you want 1/3, enter more digits (0.3333333) to get closer, or use the Fraction to Decimal page to go the other way from a fraction you already know.
Frequently asked questions
How do I convert a decimal to a fraction?
Write the decimal's digits as the numerator over the matching power of 10 (10 for one decimal place, 100 for two, and so on), then simplify. 0.8 = 8/10 = 4/5.
What is 0.8 as a fraction?
4/5 in simplest form.
Why doesn't 0.333 convert to 1/3?
Because 0.333 and 1/3 aren't actually the same number — 1/3 is the repeating decimal 0.333..., going on forever, while 0.333 is a finite value exactly equal to 333/1000. Converting what you actually typed, rather than guessing you meant the repeating version, is the mathematically honest choice.