Percentage Calculator

Find a percent of any number, the percentage increase or decrease from one value to another, or their difference, with the formula shown.

Percent of a number

What is
%
 of
?
?

Type both numbers to see the answer.

What percent

 is what percent of
?
?

Type both numbers to see the answer.

Find the whole

 is
%
 of what?
?

Type both numbers to see the answer.

Each answer updates while you type, and the working underneath uses your own numbers, so a teacher or a client can follow it.

Free with no sign-up, and the figures you type stay on this page.

  • Percentage change and difference
  • Formula with your numbers
  • Add, subtract or reverse a percent

How to calculate percentage

Pick the kind of sum, type two numbers and read the answer with its working.

  1. Calculate a percentage

    Pick a tab: Percent of, Change, Difference or Add or subtract. Type two numbers and the answer appears at once.

  2. Check the formula

    Under each answer, the working shows the formula with your own numbers in it, so you can follow it or copy it out.

  3. Copy the answer

    Press the copy button beside a result to paste it into a message, a sheet or homework, rounded the way it shows.

How to calculate percentage increase

Take the old value away from the new one, divide by the old value and multiply by 100. Rent going from 1,200 to 1,350 is a rise of 150, and 150 ÷ 1,200 × 100 gives a 12.5% increase. Type both values into the Change tab and it shows the same steps.

When the new value is smaller, the answer is negative, which is a percentage decrease: a price cut from 80 to 60 is a 25% decrease. An increase has no ceiling, so 20 growing to 50 is a 150% increase. A start of zero has no answer, because nothing can be divided by zero.

Rates need one more step. An interest rate moving from 3% to 5% is up 2 percentage points, yet up 66.67% as a percentage. The Change tab lists both, the plain difference in points and the change as a percent, so a news headline or a bank letter can be read either way.

Percentage difference formula

Percentage difference compares two values when neither one is the starting point, such as two quotes or two lab readings. Divide the gap between them by their average, then multiply by 100. For 80 and 100 the gap is 20, the average is 90, and the difference is 22.22%.

Percentage change divides by the old value instead, so 80 to 100 is a 25% increase while 100 to 80 is a 20% decrease. Percent difference against percent change comes down to one question: is one value clearly the before? If it is, use Change; if not, use Difference.

The Difference tab gives the same answer in whichever order you type the numbers, and lists the change each way underneath so you can quote the one you need. It gets unreliable near zero or when one value is below zero, where the average stops being a fair yardstick.

How to calculate percentage of marks

Add up the marks you scored in every subject, add up the maximum marks, then divide the first total by the second and multiply by 100. Put the two totals in the What percent row of the Percent of tab: 412 out of 500 shows as 82.4%.

Avoid averaging each subject's percentage when the papers are out of different totals. Scores of 45 out of 50 and 60 out of 100 average to 75%, but together they make 105 out of 150, which is 70%. The bigger paper should count for more, and adding the marks first does that.

Boards and universities set their own rules. Some count only the best five subjects, and some weight practicals or convert grades first. Check which subjects your marksheet or admission form counts, then add only those before you work out the percentage.

What this online percentage calculator does

  • Percent of a number

    Find 15% of 240 or any share of an amount, such as a tip, a tax, a deposit or a commission.

  • X is what percent of Y

    Turn a part and a whole into a percent: a test score out of 80, a budget line or a survey count.

  • Percentage change

    The rise or fall from an old value to a new one, marked as an increase or a decrease, with the gap.

  • Percentage difference

    Compare two values with no before and after, using their average, the same in either order.

  • Add or remove a percent

    Add 20% VAT to a price, take 15% off a bill, or raise a salary by 4% and see the new total.

  • Reverse percentage

    Find the number before a percent was added or taken off, such as a price before tax or a sale.

Is this percentage calculator private?

Yes. Every sum is worked out in this tab and no number is sent anywhere.

  • Processing

    Every sum runs in your browser while you type. The numbers you enter are never sent to a server.

  • Storage

    Nothing is saved. Reload or close the page and the boxes are empty again, with no history kept.

  • Account

    A free percentage calculator with no sign-up, no email and no limit on how many sums you do.

How to work out percentages

How do you calculate percentage?

Divide the part by the whole and multiply by 100. That is the formula for percentage: 30 out of 120 is 30 ÷ 120 × 100 = 25%.

How do you find the percentage of a number?

Multiply the number by the percent and divide by 100: 15% of 240 is 240 × 15 ÷ 100 = 36. The Percent of tab does it as you type.

How do you calculate percentage decrease?

Take the new value from the old, divide by the old and multiply by 100. A drop from 250 to 200 is 50 ÷ 250 × 100, a 20% decrease.

How do I calculate percentage in Excel?

Use =A2/B2, then press Ctrl+Shift+5 for the percent format. For change, use =(B2-A2)/A2 with the old value in A2, the new in B2.

How do I calculate percentage on a calculator?

On most phones, type 80 × 20 and then the % key to get 16. With no % key, type 80 × 0.2 instead, since 20% is 0.2 as a decimal.

What is a percentage point?

The plain gap between two percentages. A rate going from 3% to 5% rises by 2 percentage points, which is a 66.67% increase.

How do I calculate a percentage of a percentage?

Multiply the two and divide by 100, so 20% of 50% is 10%. Never add them: two cuts of 10% leave 81% of the price, not 80%.

What is 20 percent of 50?

It is 10. Find 10% by moving the decimal point one place left, which gives 5, then double it. Check any pair in Percent of.

Still stuck, or found a problem? Email dobliquestudio@gmail.com and we will help.

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