Percentage Change Calculator

Calculate, compare, and interpret percentage change for prices, revenue, scores, investments, and everyday numbers. Read the definitions and formulas on this page first, then use the two-field tool when you are ready.

What is percentage change? Open calculator

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Change monitor LIVE

Prior: 120.00
Current: 138.00
Delta: +15.00%
Layout: 2 inputs

Percentage change calculator

Two inputs, one result, and a short line that states increase, decrease, or no net change. Your entries stay in the browser on this static build.

Original value

New value

Percentage change

Enter both values to see the result.

Result = ((new − original) ÷ |original|) × 100. When the original is zero, the relative change is undefined.

Example calculations (try these in the fields)

List price to sale price 200 to 160 Expect −20%, a twenty percent decrease from the list baseline.
Users last month to this month 8000 to 9200 Expect +15%, a fifteen percent increase versus last month.
Exam score 72 to 81 Expect +12.5% relative to the earlier score as baseline.

What is percentage change?

Percentage change is a way to describe how much a number moved from an original value to a new value, expressed as a percent of that starting point. It answers "how big was the move compared to where we began?" rather than "how many units did we add or subtract?"

Meaning depends on direction. A positive percentage change means the new value is larger than the original. A negative percentage change means it is smaller. Near-zero results usually mean little movement, subject to rounding.

Percentage change differs from percentage difference in common usage. Change compares new to a chosen baseline over time or context. Difference often compares two peers without naming one as the temporal "original." See the section below and the linked article for careful wording.

It matters because stakeholders think in relative terms: a five dollar move on a ten dollar item is huge, while the same five dollars on a thousand dollar baseline is small. Percent change standardizes that intuition.

Real-life uses include price tags, sales growth, salary adjustments, population estimates, grades, and portfolio snapshots. The same formula appears in statistics and business reporting whenever you need a comparable scale.

Percentage change formula

percentage change = ((new value − original value) ÷ |original value|) × 100%

Increase and decrease use the same expression. The sign of (new − original) tells you whether it is an increase or a decrease.

Positive versus negative results come straight from the numerator. The denominator uses the absolute value of the original so behavior stays consistent when the baseline is negative.

If the original value is zero, do not divide. Relative change versus zero is undefined because there is no stable baseline.

How to calculate percentage change

These steps match what the calculator does so you can reproduce the result by hand, in a sheet, or in code.

1 Write down the original value (the baseline you compare against).
2 Write down the new value (the updated measurement).
3 Subtract: new minus original.
4 Divide that difference by the absolute value of the original.
5 Multiply by one hundred and attach a percent sign.

Manual method

Use paper or a basic calculator with the formula above. Keep extra decimal places until the final step, then round for display.

Calculator method

Jump to the tool on this page, enter original and new values, and read the percentage plus the increase or decrease line under the result.

Spreadsheet method

If original is in A1 and new is in B1, a common pattern is =(B1-A1)/ABS(A1). Format the cell as a percentage or multiply by one hundred according to your convention.

Shortcut checks

If the new value doubled, expect about +100%. If it halved, expect about −50%. If the baseline is tiny, expect large magnitudes even for modest absolute moves.

Percentage change examples

Each example uses the same formula: ((new − original) ÷ |original|) × 100%.

Price increase

Original 80, new 100

The change is +25%. Customers see a twenty dollar bump on an eighty dollar baseline.

Revenue growth

Original 420000, new 483000

The change is +15%. Useful for quarter-over-quarter headlines when the story is relative scale.

Salary increase

Original 55000, new 57200

The change is +4%. The absolute raise is two thousand two hundred, but percent change communicates impact versus prior pay.

Population change

Original 125000, new 121250

The change is −3%. Helpful for planning when you need a single comparable figure.

Investment balance

Original 10000, new 10850

The change is +8.5%. Pair with time span separately, since one interval percent change is not the same as an annualized rate.

Read the longer examples article on the blog

Percentage increase calculator

Any time the new value is larger than the original, the percentage change is positive. Sales growth, inflation from a lower index to a higher index, and enrollment gains all read as increases when you use the standard formula.

Business teams often report growth as percent change so managers can compare divisions or products that have different unit scales.

Inflation and "percent up" language in the news still rely on the same baseline logic: pick the reference period, then compare the new level to it.

Article: percentage increase calculator and growth framing

Percentage decrease calculator

When the new value is smaller than the original, the percentage change is negative. Discounts from list price, revenue declines, depreciation, and loss percentages all show up as decreases if you name the higher figure as the original.

A fifty percent decrease means the new value is half of the original. A one hundred percent decrease (rare in finance wording) would mean the new value hit zero from a positive start.

Keep absolute dollars in view. A small percent cut on a huge contract can matter more than a large percent cut on a tiny line item.

Article: percentage decrease calculator and reduction framing

Percentage change vs percentage difference

Percentage change names an original and asks how far a new value moved relative to that baseline. It is directional and narrative: "from last quarter to this quarter."

Percentage difference language sometimes compares two measurements symmetrically, such as the midpoint between two lab readings, depending on your textbook or style guide. Mixing the two phrases without defining terms is a common mistake.

Formula comparison: classic percent change uses the original in the denominator. Some difference formulas average the two values in the denominator. Those are not interchangeable numbers.

Correct usage means telling readers which value is the baseline and whether you used an averaged denominator. Real-world examples appear in the linked article.

Article: formulas, mistakes, and examples for change versus difference

Percentage growth rate

Simple percentage change between two dates is a good starting point for trend analysis. It answers "how much did we move between point A and point B?"

When you need growth per period, you might quote monthly or annual figures. Be explicit about the interval: a ten percent move over one month is not comparable to ten percent over one year without more context.

Compound growth and forecasting deserve their own labels. Once the primary percent change question is clear, you can extend to compound annual growth rate (CAGR) or average percentage change across several periods using dedicated definitions.

CAGR versus one-step percentage change · Average percentage change across multiple intervals

Common percentage change mistakes

Swapping original and new. Putting the wrong value in the denominator changes the story. Always fix the baseline first, then measure the move to the updated figure.
Dividing by zero. Starting from zero makes relative percent undefined. Use absolute change or pick a different baseline.
Mixing up percentage points. Moving a rate from 4% to 5% is one percentage point and also a twenty five percent increase relative to the 4% baseline. Use the label your readers expect.
Forgetting the sign. A negative result is information, not an error. Check business context before you flip signs to "make it look positive."
Comparing unlike periods. A twelve percent change over a week is not comparable to twelve percent over a year without saying so explicitly.

Percentage change vs percentage points

Percentage change divides by a baseline to express relative size. Percentage points subtract two percentages to describe an arithmetic gap between rates.

Headlines mix these terms. When both numbers are already percents (interest, tax rates, survey shares), ask whether readers need points (simple gap) or percent change (relative to the old rate).

This site’s tool is built for two raw numbers you treat as original and new. For rate-to-rate wording, see the blog article below.

Article: difference, change, and points in one place

FAQs about percentage change

Is percentage change the same as percentage difference?

Not always. Many writers use "percentage change" when there is a clear before and after with one baseline. "Percentage difference" sometimes refers to symmetric comparisons. Define your denominator and see the versus-difference section on this page.

Why does the tool show N/A when the original is zero?

Division by zero is not valid. With a zero baseline, relative percent change is undefined, so the page shows N/A instead of a misleading large number.

Can the original be negative?

Yes. The calculator divides by the absolute value of the original so the sign of the result tracks whether the new value rose or fell in a consistent way.

How is this different from CAGR?

One percentage change step compares two values. CAGR summarizes a smooth constant growth rate across multiple years. Use the blog article on CAGR versus percentage change when you need multi-year summaries.

Can I use this for discounts?

Yes, if you set the original to the pre-discount price and the new value to the price paid. The result is the percent decrease from the list or sticker baseline.

Does rounding matter?

Yes for reporting. Keep guard digits while calculating, then round at the end to the precision your audience expects, and state that precision when it matters.