Percentage Calculator
Seven percentage calculations that update as you type
What is X% of Y?
X is what % of Y?
Percentage change from X to Y
X is Y% of what?
Increase or decrease X by Y%
What number, increased or decreased by Y%, gives X?
Percentage difference between X and Y
About Percentage Calculator
Percentage Calculator has seven panels, each answering one question: what X% of Y is, what percent X is of Y, the percentage change from X to Y, the number that X is Y% of, X increased or decreased by Y%, the number that a Y% increase or decrease turned into X (a price before a discount or before tax), and the percentage difference between X and Y. Results appear as you type, with up to 10 significant digits and no rounding of small values to zero, and each panel keeps its own numbers. A division by zero is reported instead of a made-up value.
Example
Each panel with sample numbers and the result it shows (the page's own formulas, run in Node on October 18, 2026).
You enter
What is 15% of 80? 12 is what % of 80? Change from 60 to 72 Change from 72 to 60 12 is 15% of what? Increase 80 by 15% Decrease 80 by 15% 68 after a 15% decrease, from what? Difference between 60 and 72
Result
12 15% 20% -16.66666667% 80 92 68 80 18.18181818%
How to calculate a percentage
- 1Find the panel for your question, from "What is X% of Y?" down to "Percentage difference between X and Y".
- 2Type the two numbers in that panel; in "Increase or decrease X by Y%", also choose "Increase" or "Decrease".
- 3Read the result under the fields: it changes as you type, and there is no button to press.
Formats and limits
- Calculations
- X% of Y; X as a percent of Y; change from X to Y; X is Y% of what; X increased or decreased by Y%; the number a Y% increase or decrease turned into X; difference between X and Y
- Change formula
- (Y − X) ÷ |X| × 100, so the sign follows the direction even when X is negative
- Difference formula
- |X − Y| ÷ (|X + Y| ÷ 2) × 100, the same whichever number comes first
- Basic formulas
- X% of Y = X × Y ÷ 100; X as a percent of Y = X ÷ Y × 100; X is Y% of what = X × 100 ÷ Y
- Increase, decrease, reverse
- X × (1 ± Y ÷ 100) for X increased or decreased by Y%; X ÷ (1 ± Y ÷ 100) for the number that became X
- Precision
- Up to 10 significant digits; very small results are written out, not rounded to zero
- Zero
- Cannot divide by zero when the base is 0 or when the reverse panel is given a 100% decrease; Undefined when X + Y = 0 in the difference panel
- Limits
- Negative numbers and decimals are accepted in every field; a result beyond about 1.8 × 10^308, the largest number a browser holds, shows "Result too large to show"
Common uses
- Turning a test score into a percentage
- A teacher with a mark of 42 out of 50 types 42 and 50 in "X is what % of Y?" and reads 84%, the figure most grade scales use.
- Checking a raise or a price change
- A salary that goes from $52,000 to $54,600 is a change of 5% in "Percentage change from X to Y"; type the amounts as 52000 and 54600, because the number fields do not take thousands separators. The same panel measures a rent or a subscription increase.
- Comparing two quotes for the same job
- Two contractors quote $1,200 and $1,350. Neither is a starting value, so "Percentage difference between X and Y" fits: it shows 11.76470588%, the gap divided by the average of the two quotes.
- Taking sales tax out of a receipt total
- A bill of 64.80 includes 8% sales tax. Choose "Increase" in "What number, increased or decreased by Y%, gives X?" and type 64.80 and 8: it shows 60, the price before tax, so the tax was 4.80. The same steps take VAT out of a European price.
Which tool to use
- Scientific Calculator: type a percentage as part of a longer formula on one line: its engine reads 80*15% as 12 and 200 + 10% as 220. This page answers one question per labeled panel and needs no syntax.
- Fraction Calculator: when a share must stay exact, such as 1/3 of a quantity: it gives the reduced fraction and the decimal with its repeating digits in brackets, where this page stops at 10 significant digits.
- Statistics Calculator: for the mean, median, or standard deviation of a whole list of values; this page compares two numbers at a time.
Where your numbers are processed
The seven panels apply their formulas in your browser, and your numbers are neither sent nor stored: the fields are empty again when you reload. A crash of the calculator is reported to our error monitoring as a cleaned error message with the tool's name and your browser's name and major version, never the numbers in the seven panels.
Frequently asked questions
Is percentage change the same as percentage difference?
No. Change measures a move from a starting value, so the order matters: 60 to 72 is a rise of 20 percent, 72 to 60 a fall of about 16.67 percent. Difference compares two values with no start, dividing the gap by their average. The third and seventh panels give each.
Does a 20 percent rise followed by a 20 percent fall bring me back to the start?
No. The fall applies to the larger amount: 100 rises to 120, and taking 20 percent off 120 leaves 96. Undoing a 20 percent rise takes a fall of 20 ÷ 120, about 16.67 percent, which the "Increase or decrease X by Y%" panel lets you check.
Can a percentage change go below minus 100 percent?
Yes, when the new value is negative. The page divides by the absolute value of the starting number, so 10 to −5 is a change of −150 percent, and −10 to −5 counts as a rise of 50 percent, since the value went up.
What if the starting value is 0?
No percentage can be given, because it would mean dividing by zero: a change from 0, X as a percent of 0, and X is 0 percent of what all show "Cannot divide by zero", as does a 100 percent decrease in the reverse panel, since a number decreased by 100 percent always becomes 0. The difference panel shows "Undefined" when the two numbers add up to 0.
How many decimals does it show?
10 significant digits at most, without rounding small results to zero: 0.001 percent of 5 shows 0.00005, where a two-decimal display would show 0.00. Round money amounts to cents yourself before using them.
How do I work out a percentage of a number?
Multiply the number by the percentage and divide by 100: 15 percent of 80 is 80 × 15 ÷ 100 = 12. Type 15 and 80 in "What is X% of Y?" and the panel shows 12.
Can a percentage be more than 100?
Yes, whenever the part is larger than the whole you compare it with: 150 is 250 percent of 60. "X is what % of Y?" has no upper limit, and "Percentage change from X to Y" gives 150 percent for a value that went from 40 to 100.
What is the difference between percent and percentage points?
Percentage points are the plain gap between two rates, while percent is the relative change: an interest rate going from 10 to 12 percent rises by 2 percentage points but by 20 percent. Enter 10 and 12 in "Percentage change from X to Y" for the 20 percent; the 2 points are a subtraction, so no panel is needed for them.
How do I take a discount off a price?
Choose "Decrease" in "Increase or decrease X by Y%", then type the price and the discount: 79.99 with 25 percent off shows 59.9925, which you round to 59.99. The amount saved comes from "What is X% of Y?" with 25 and 79.99.
How do I find the original price before a discount?
Divide the sale price by what is left after the discount instead of adding the discount back: a jacket at 68 after 15 percent off cost 68 ÷ 0.85 = 80. Adding 15 percent to 68 gives 78.2, because the 15 percent was taken from 80, not from 68. Choose "Decrease" in "What number, increased or decreased by Y%, gives X?", type 68 and 15, and the panel shows 80.
How do I calculate a percentage increase between two numbers?
Subtract the old value from the new one, divide by the old value, and multiply by 100: a rent going from 1,250 to 1,325 rises by 75 ÷ 1,250 × 100 = 6 percent. Type 1250 and 1325 in "Percentage change from X to Y"; a fall shows as a negative percentage in the same panel.
How do I turn a fraction or a decimal into a percentage?
Multiply a decimal by 100: 0.156 is 15.6 percent, and 15.6 percent divided by 100 is 0.156 again. For a fraction, type its top and bottom numbers in "X is what % of Y?": 3 and 8 show 37.5%, so 3/8 is 37.5 percent.
Can I calculate per mille or basis points?
Yes, by converting first: 1 per mille (‰) is 0.1 percent and 1 basis point is 0.01 percent, so divide per mille by 10 and basis points by 100 before typing them. A fee of 25 basis points on 2,000,000 is 0.25 percent: "What is X% of Y?" with 0.25 and 2000000 shows 5000.
Tips and tricks
- ✓To find a price before a discount, use "What number, increased or decreased by Y%, gives X?" with "Decrease", the sale price and the discount; "X is Y% of what?" gives the same answer from the share of the full price you paid.
- ✓To add a tip or a tax to a bill, "Increase or decrease X by Y%" gives the total in one step.
Related tools
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- Statistics Calculator — mean, median, mode, standard deviation, quartiles, and outliers of a list of numbers.
- Scientific Calculator — expressions with powers, roots, logarithms, and trigonometry.
- Currency Converter — convert an amount between currencies at the daily exchange rate.
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