Percentage Calculator is a free online tool to calculate percentages.
A percent is a number of hundredths, so every percentage question is some arrangement of dividing by 100 and multiplying. Each of the three questions above works one of those arrangements. Here is what each does, with the working set out.
A percent is hundredths, so 15% is 15 hundredths. Divide the percentage by 100 to get that fraction, then multiply it by the number you are taking it from. Percentages of a total — a tip, a discount, a tax — are all this question.
What is 15% of 80?15 ÷ 100 × 80 = 12
Divide the part by the whole to get the fraction one is of the other, then multiply by 100 to read that fraction as a percentage. Scores, shares and completion rates are all this question. Which number is the whole matters: it is the one you are measuring against.
30 is what percent of 120?30 ÷ 120 × 100 = 25
Take the difference between the two numbers, then read it as a percentage of where you started. Starting from 40 rather than 50 is what makes the same 10 a rise of 25% rather than a fall of 20% — a change is always measured against the number it started from. A negative answer is a decrease.
What is the percentage increase/decrease from 40 to 50?(50 − 40) ÷ 40 × 100 = 25
Divide the percentage by 100, then multiply by the number you are taking it from. 15% of 80 is 15 ÷ 100 × 80, which is 12. This is the question behind tips, discounts, tax and commission.
Divide the part by the whole, then multiply by 100. 30 out of 120 is 30 ÷ 120 × 100, which is 25%. Take care which number is the whole: it is the one you are measuring against, and swapping the two gives a different percentage.
Subtract the starting number from the ending number, divide by the starting number, then multiply by 100. From 40 to 50 is (50 − 40) ÷ 40 × 100, which is a 25% increase. A negative answer is a decrease. The change is always measured against where you started, which is why going from 40 to 50 and back again are not the same percentage.
Because some questions have no percentage to give, even filled in correctly. Nothing is a percentage of zero, so asking what percent a number is of 0 has no answer. A change measured from zero has no answer either, and neither does one from a negative starting number, because the sign would flip and report a rise as a fall. The question says which of these it ran into rather than only showing that it could not answer.
To two decimal places, with trailing zeros dropped, and ties rounded away from zero. An answer too small to survive two places keeps its significant digits instead, so you are never shown 0 for an answer that is not zero. An answer too long to read is shown in exponent form, which is shorter and no less true.
Digits, a single decimal point, and a minus sign at the front, up to 15 characters. Thousands separators are not accepted, so type 1000 rather than 1,000. A character a question will not take is refused visibly and the reason is shown beside the blank — it is never dropped quietly, which would leave you holding a different number than the one you typed.
No. Every answer is worked out in your browser. The numbers you type into the blanks are never sent anywhere, are not written down, and are gone when you close the page. The site has no accounts and asks for nothing about you. It does run Google Analytics, which gives your browser a lasting identifier and records which pages it visits — not tied to your name, but not merely a total either. The privacy policy sets out what that collects and how to stop it.