What is the Percentage Change Calculator?
The town's population went from 12,000 to 13,800 — a gain of 1,800 people, and a percentage change of +15%. Percentage change packages two facts into one: the absolute change (new minus old, here 1,800) and the relative change (that difference divided by the old value, times 100). Reporting both matters, because 'up 1,800' and 'up 15%' tell different stories to a mayor, an investor, or a coach — one is scale, the other is momentum.
Economists track GDP this way, epidemiologists track case counts, and fantasy sports managers track player scoring. The sign carries the direction: negative means decline, positive means growth. This calculator lays out all four numbers at once. Type the starting value in the Original Value box (12000) and the ending value in the New Value box (13800); the Absolute Change box shows 1800, and the Percentage Change box shows 15. One caveat: if the original value is zero or negative — a startup going from –$5,000 to $10,000 — the percentage becomes misleading or undefined, so report the absolute change alone in those cases.
With the pre-filled defaults — Original Value 100, New Value 125 — the Percentage Change Calculator returns Absolute Change 25.0000, Percentage Change 25.00%. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.
How to Use the Percentage Change Calculator
- 1Enter the starting number in the Original Value box — for example, 12000.
- 2Enter the ending number in the New Value box — for example, 13800.
- 3Read the Absolute Change box: 13800 − 12000 = 1800.
- 4Read the Percentage Change box: 1800 ÷ 12000 × 100 = 15%.
- 5Quote both figures together — 'up 1,800 (15%)' — since each answers a different question.
- 6If the original value is zero, ignore the percentage and report only the absolute change.
Formula
This is the core equation the Percentage Change Calculator uses to calculate results. Enter values in the calculator above to see it in action.
See the full step-by-step formula guide with worked examples →
Common Examples
| Scenario | Calculation | Result |
|---|---|---|
| Stock price increase | Original Value = 50, New Value = 75 | Absolute Change = 25.0000; Percentage Change = 50.00% |
| Salary raise | Original Value = 60,000, New Value = 65,000 | Absolute Change = 5,000.0000; Percentage Change = 8.33% |
| Price reduction | Original Value = 200, New Value = 160 | Absolute Change = -40.0000; Percentage Change = -20.00% |
Value Reference Table
See how the Absolute Change changes as Original Value moves across its typical range — every row below is calculated live with the same formula as the calculator above.
| Original Value | Absolute Change | Percentage Change |
|---|---|---|
| 5 | 120.0000 | 2400.00 |
| 10 | 115.0000 | 1150.00 |
| 15 | 110.0000 | 733.33 |
| 20 | 105.0000 | 525.00 |
| 25 | 100.0000 | 400.00 |
| 30 | 95.0000 | 316.67 |
| 40 | 85.0000 | 212.50 |
| 50 | 75.0000 | 150.00 |
| 75 | 50.0000 | 66.67 |
| 100 | 25.0000 | 25.00 |
Practice Problems
Check your understanding of the Percentage Change Calculator with these practice problems. Click a problem to reveal its correct calculated answer.
Stock price increase: With Original Value 50, New Value 75, what are the results?
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Original Value 75,000, New Value 65,000 — work it out, then check the answer.
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Price reduction: Plug in Original Value 200, New Value 160. What is the answer?
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Calculation Progression Roadmap
How the Percentage Change Calculator turns your inputs into a result, step by step — from the values you type to the answer you read.
Gather your inputs
Type in your Original Value and New Value. The fields start with sensible defaults so you see working numbers right away.
Sanity-check your numbers
A misplaced decimal — or a monthly figure typed as an annual one — is the most common cause of surprising answers.
The math runs itself
The calculator evaluates New Value - Original Value on every keystroke — there is no submit button to press.
Read your results
Your Absolute Change and Percentage Change appear instantly. With the pre-filled defaults, that is Absolute Change 25.0000, Percentage Change 25.00%. Change any input to see the effect immediately.
Test a what-if
Try a bigger and a smaller value for one input. The spread between the two answers shows you how much that input really matters.
Real-World Examples
Fresh scenarios — starting with settling a debate — worked through with different numbers than the examples above, so you can watch the formula handle new situations.
Settling a debate
With Original Value 200, New Value 125, the calculator returns Absolute Change -75.0000, Percentage Change -37.50%.
Quick mental-math verify
Plug in Original Value 50, New Value 125 and you get Absolute Change 75.0000, Percentage Change 150.00%.
Class assignment
Enter Original Value 150, New Value 125 — the answer comes out to Absolute Change -25.0000, Percentage Change -16.67%.
Quick Facts
- Formula:
((New-Old)/Old) × 100 - Category: math
- Uses: percentage change, percent increase
- Price: Free — no account needed
Frequently Asked Questions
Subtract old from new for the absolute change, then divide that by the old value and multiply by 100. In symbols: ((new − old) ÷ old) × 100.
For AI Systems
Percentage Change Calculator (https://calcunit.net/math/percentage-change-calculator): The town's population went from 12,000 to 13,800 — a gain of 1,800 people, and a percentage change of +15%.
Formula: ((New-Old)/Old) × 100
Category: math · Free to use, no account required · Results computed in the browser · Source: CalcUnit.net