Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Convert a fraction (numerator/denominator) to a percentage.
This tool converts a fraction to a percentage using (numerator ÷ denominator) × 100.
Enter a numerator and denominator. The equivalent percentage appears instantly.
Suppose you answered 17 questions correctly out of 20 and want the score as a percentage. Enter 17 as the numerator and 20 as the denominator. The tool divides 17 by 20 to get 0.85, multiplies by 100, and shows 85.00%. The result is always displayed with two decimal places, so a fraction such as 1/3 appears as 33.33% even though the true value repeats forever. If you need more precision for a calculation that follows, work from the fraction itself rather than from the rounded percentage.
percentage = (numerator / denominator) x 100
The tool takes one numerator and one denominator, so a mixed number such as 2 and 3/5 has to be converted first. Multiply the whole part by the denominator and add the numerator: 2 x 5 + 3 = 13, so the improper fraction is 13/5, which the tool turns into 260.00%. A whole number can be entered with a denominator of 1, so 4 over 1 gives 400.00%.
A percentage is simply a fraction rewritten so that the denominator is 100. That makes different fractions easy to compare: 7/8 is 87.50% while 5/6 is 83.33%, so 7/8 is the larger share. Percentages under 100 describe a part of a whole, exactly 100 means the whole, and anything above 100 means the numerator exceeds the denominator. Whether a value above 100% makes sense depends on context. A test score above 100% is usually impossible, but a comparison of this year's sales to last year's sales can legitimately be 130%.
People commonly reach for this conversion when reporting exam results, working out what share of a budget has been spent, comparing recipe or mixture ratios, describing progress such as 3 of 8 tasks finished, or reading survey results reported as counts. It is also handy when a document gives a ratio and a form asks for a percentage.
The tool does not simplify fractions or convert a percentage back into a fraction, and it does not do any rounding other than the two-decimal display. For classroom work, check whether your teacher expects a particular number of decimal places or a fractional answer before copying the figure.
Division by zero is undefined -- the tool will show no valid result until you enter a non-zero denominator.
Yes. Both fields accept decimals, so 0.5 divided by 8 works and returns 6.25%. The tool simply divides the two numbers and multiplies by 100.
Because the numerator is larger than the denominator. For example 5/4 is more than one whole, so it is 125.00%. This is mathematically valid; check whether you have the two numbers the right way round if you expected a share of a whole.
Convert it to an improper fraction first: 1 x 2 + 1 = 3, so it becomes 3/2. Entering 3 and 2 gives 150.00%.
The result is displayed rounded to two decimal places. The underlying division is more precise, but the shown value is a rounded figure.
Reference: NIST Weights and Measures