Percentage Change Calculator measures how far a value moved from an original number to a new one, expressed as a signed percent. Enter the starting value and the ending value, and the tool returns a positive percent for growth or a negative percent for decline, with the substitution shown.
Compute the signed percent change
The percent change formula divides the change by the original value, then multiplies by 100: P equals (Y minus X) divided by X, times 100. A subscription that moves from $40 to $52 gives (52 − 40) / 40 × 100, which is 30 percent.
A price that drops from $80 to $68 gives (68 − 80) / 80 × 100, which is −15 percent. The sign tells you the direction; the calculator never strips it.
Read the ten linked modes
Percentage Change Calculator sits on the same ten-mode engine as the general percent calculator, so a single page also finds P percent of X, recovers the whole from a part and a percent, and applies a known rate as a markup or markdown.
The change mode is selected first because it answers the most common question: by what percent did this move?
Apply a percent change to get the new value
Reverse the formula to project forward. Given an original value X and a known percent change P, the new value Y equals X times (1 plus P divided by 100). A $500 tool that appreciates 8 percent becomes 500 × 1.08, which is $540.
A $500 tool that depreciates 8 percent becomes 500 × 0.92, which is $460. The sign of P controls whether the multiplier sits above or below 1.
Recover the original value from a change
When the new value and the percent change are known but the starting point is missing, divide instead of multiply. X equals Y divided by (1 plus P divided by 100). A phone bill grew 12 percent to reach $89.60; dividing 89.60 by 1.12 recovers an original bill of $80.
This mode matters for tax-inclusive prices and salary figures quoted after a raise.
Percentage points are not percent change
Many readers confuse a change measured in percentage points with a percent change measured relatively. An interest rate that moves from 4 percent to 6 percent rose by 2 percentage points, but the percent change is (6 − 4) / 4 × 100, which is 50 percent.
Percentage Change Calculator only reports the second number: the relative change, not the raw point gap. Financial reporting that blends the two produces headlines that overstate or understate the real shift.
Avoid this common mistake
A frequent error treats the new value as the base instead of the original value. Computing (52 − 40) / 52 × 100 for the subscription example above gives roughly 23.1 percent, not 30 percent. The denominator in percent change is always the starting value, never the ending one, because percent change measures growth relative to where a quantity began.
Work through a website traffic example
A website's monthly visitors move from 24,000 to 30,000. The percent change is (30,000 − 24,000) / 24,000 × 100, which is 25 percent. Confirming in reverse, a 25 percent increase on 24,000 gives 24,000 × 1.25 = 30,000, matching the reported new total exactly and verifying the found percent is correct.
Use percentage change to compare two different periods
Percentage change is often used to compare growth across two different time spans of different lengths, such as a 25 percent rise over one month against a 40 percent rise over three months.
Comparing the raw percentages alone can be misleading, since the longer period had more time to compound; converting each to an average per-period rate, using the compound growth formula solved backward for the periodic rate, gives a fairer side-by-side comparison than the raw totals do.
Frequently asked questions
What is the formula for percentage change?
The formula for percentage change is P = ((Y − X) / X) × 100, where X is the original value and Y is the new value. A positive result means growth; a negative result means decline.
How do you calculate a 20 percent increase?
To calculate a 20 percent increase, multiply the original value by 1.20. A base price of $150 becomes 150 × 1.20, which is $180. Percentage Change Calculator applies this multiplier directly in its add_y mode.
How do you calculate a percentage decrease?
To calculate a percentage decrease, multiply the original value by 1 minus the rate as a decimal. A $60 item marked down 25 percent becomes 60 × 0.75, which is $45.
Why is my percentage change negative?
A percentage change comes out negative whenever the new value is smaller than the original value, since Y minus X is negative in that case. A negative sign in the answer means the quantity fell, not that a calculation error occurred.
What is the difference between percentage change and percentage points?
Percentage change is a relative measure of growth or decline against the original value, while percentage points measure the raw arithmetic gap between two percents. Moving from 10 percent to 12 percent is 2 percentage points and a 20 percent relative increase at the same time.
Can percentage change be over 100 percent?
Percentage change exceeds 100 percent whenever a value more than doubles. Going from 10 to 25 gives (25 − 10) / 10 × 100, which is 150 percent, because the increase itself is larger than the starting value.
What is the percentage change from 24,000 to 30,000?
The percentage change from 24,000 to 30,000 is 25 percent, found by dividing the 6,000 increase by the original 24,000 and multiplying by 100.
Can you directly compare percentage changes over different time periods?
Percentage changes over different time periods cannot be directly compared without adjustment, since a larger raw percentage over a longer period may actually represent slower per-period growth than a smaller percentage over a shorter period; converting each to an equivalent periodic rate gives a fair comparison.
Summary
Percentage Change Calculator returns the signed percent between an original and a new value using P = ((Y − X) / X) × 100, and it runs the same formula in reverse to project a new value or recover an original one.
Enter any two of the three quantities: original value, new value, or percent change, and read the third with the substitution shown. Remember that percent change always divides by the starting value, not the ending one.