Math

Instant, private, and free

Percentage Converter.

Convert a percentage to a decimal, a decimal to a percentage, a percentage to a fully reduced fraction, or a percentage to a probability with 1-in-N and odds.

On-device calculationNo signup
01

Set your values

Results update as you type.

Convert

How to Use

Percent literally means 'per hundred'. To go from a percentage to a decimal, divide by 100 (move the point two places left): 25% → 0.25. To go back, multiply by 100: 0.25 → 25%.

Fractions are always reduced to lowest terms, so 25% comes back as 1/4 rather than 25/100, and 12.5% as 1/8.

Results are rounded to remove binary floating-point noise, so 10% converts to exactly 0.1. Fractions honour up to 6 decimal places of the percentage; repeating values such as 33.333…% are marked as approximate.

FAQs

How do I convert a percentage to a decimal?

Divide by 100, which is the same as moving the decimal point two places to the left: 25% → 0.25, 7% → 0.07, 150% → 1.5, 0.5% → 0.005. To go the other way, multiply by 100 and add the % sign.

What is 25% as a fraction?

1/4. Writing it as 25/100 is correct but not reduced — dividing the top and bottom by their greatest common divisor, 25, gives 1/4. This converter always reduces to lowest terms, so you get 1/4, not 25/100. Similarly 12.5% is 1/8, 75% is 3/4 and 150% is 3/2 (or 1½).

What does a percentage mean as a probability?

A 25% chance is a probability of 0.25, which is the same as '1 in 4', with odds in favour of 1:3 (one way it happens for every three ways it does not). Note that odds and probability are not the same thing: 1:3 odds means 1/4 probability, not 1/3.

Why does 0.1 sometimes show as 0.10000000000001 in other calculators?

Computers store decimals in binary, where values like 0.1 have no exact representation, so 0.1 × 100 can come out as 10.000000000000002. This converter rounds every result to a fixed precision before displaying it, so 10% converts to exactly 0.1 and 0.07 converts to exactly 7%.

How do I write a repeating percentage like 33⅓% as a fraction?

Exactly, it is 1/3. Typing 33.333% here gives 33333/100000, because that is literally the number you entered. The converter honours up to six decimal places of the percentage and flags the result as approximate when the value had to be rounded, so you can tell an exact fraction from a near-miss.

Cite this calculator

Canonical URL: https://mathify.one/zh/math/percent-converter

Cite as: Mathify. (2026). 百分比换算器. https://mathify.one/zh/math/percent-converter

Use Cases

Academic and Homework Help

Students can quickly convert percentages to fractions and decimals for math assignments, ensuring accurate and simplified results.

Example: Convert 37.5% to a fraction and decimal.

Probability and Odds Interpretation

For games, statistics, or risk assessment, convert a percentage chance into a 1-in-N format or odds to better understand likelihood.

Example: A 20% chance becomes 1 in 5.

Frequently Asked Questions

How do I convert a percentage to a decimal?
Divide the percentage by 100. For example, 25% becomes 0.25. The calculator does this instantly and exactly.
What does '1-in-N' probability mean?
It expresses a probability as a ratio of 1 success in N trials. For instance, 25% probability is equivalent to 1 in 4. The calculator converts your percentage to this format.
Can I convert a decimal back to a percentage?
Yes, the calculator also supports converting decimals to percentages. Simply enter a decimal like 0.75, and it will show 75%.

Tips & Common Mistakes

Tips

  • Use the calculator to verify your manual conversions, especially when dealing with repeating decimals like 33.33%.
  • When converting to odds, remember that odds represent the ratio of success to failure, not the probability itself.
  • For exact fraction results, the calculator reduces fractions to their simplest form automatically.
  • Double-check your input format: percentages should be entered as numbers without the '%' symbol unless specified.

Common Mistakes to Avoid

  • Forgetting to divide by 100 when converting a percentage to a decimal manually.
  • Assuming that 1-in-N odds are the same as the probability percentage; they are different representations.
  • Entering a percentage as a decimal (e.g., 0.25 instead of 25) without adjusting the conversion.

Last updated: August 13, 2026