Percentage Change Calculator
See exactly how much a value changed from one period to another, and whether it went up or down.
How It Works
You enter two numbers: the original (earlier) value and the new (later) value. The calculator subtracts the original from the new, divides by the absolute original value, then multiplies by 100. A positive result is an increase. A negative result is a decrease.
Percentage Change = (Change / |Original Value|) × 100
Example (decrease): 100 to 72 = ((72 – 100) / 100) × 100 = -28%
The absolute value of the original is used in the denominator so the formula works correctly even when the original value is negative. The calculator also shows the multiplier (how many times bigger the new value is relative to the original), which is useful for investment and business contexts.
When People Actually Need This
Salary and income changes
You’re earning $50,000 and get a raise to $55,000. That’s a 10% increase. You need that number to compare against inflation, to negotiate further, or to benchmark against peers. This calculator gives it to you in under five seconds, along with the exact dollar amount of the raise ($5,000).
Month-over-month and year-over-year reporting
Your team’s revenue was $43,000 last month and $51,600 this month. That’s a 20% increase. Or traffic was 28,000 last quarter and 21,000 this quarter. That’s a 25% decrease. Both numbers need to go in a report, and calculating percentage change under deadline pressure is exactly when mistakes happen. One tool, two inputs, instant answer.
Price and cost changes
Rent went from $1,200 to $1,380. That’s a 15% increase. A supplier raised their unit price from $4.50 to $5.10. That’s a 13.33% increase. Percentage change gives these numbers a single, comparable figure that’s much easier to act on than a raw dollar difference.
Investment performance
A stock was bought at $42 and is now at $67.20. That’s a 60% gain. A portfolio was worth $18,500 and is now worth $15,170. That’s an 18% loss. Both figures matter for decisions about holding, selling, or rebalancing.
Exam scores and academic results
A student scored 65 on a first test and 82 on a resit. That’s a 26.15% improvement. Or a class average dropped from 74 to 68. That’s an 8.11% decrease. Percentage change puts score movements in perspective and helps identify whether improvement is meaningful or marginal.
Table of Truth: Common Changes and Results
Use this table to sanity-check your result or estimate before entering your numbers.
| Original | New Value | Change | Amount |
|---|---|---|---|
| 50 | 75 | +50.00% | +25 |
| 100 | 72 | -28.00% | -28 |
| 50,000 | 55,000 | +10.00% | +5,000 |
| 1,200 | 1,380 | +15.00% | +180 |
| 43,000 | 51,600 | +20.00% | +8,600 |
| 200 | 150 | -25.00% | -50 |
| 42 | 67.20 | +60.00% | +25.20 |
| 18,500 | 15,170 | -18.00% | -3,330 |
| 65 | 82 | +26.15% | +17 |
| 1,000 | 1,000 | 0.00% | 0 |
Percentage Change vs Percentage Difference: Which One?
Common Mistakes People Make
Real-Life Examples
HR preparing a pay review report
An HR manager needs to report that the average employee salary moved from $62,000 to $66,340 after the annual review cycle. That’s a 7% increase. With that number, leadership can compare the outcome against the 6% budget target and inflation figures for the period. The raw dollar number ($4,340 average raise) is also shown, which is useful for cost modelling.
E-commerce tracking conversion rate change
A website’s checkout conversion rate was 2.4% in March and 3.1% in April. The percentage change is 29.17%. A 29% improvement in conversion rate is a significant result. The team can now report this to stakeholders as a validated metric, not just a “it went up a bit” statement.
Tenant documenting a rent increase
Rent went from $950 per month to $1,140. That’s a 20% increase. Local regulation caps rent increases at 10% per year. The tenant now has the exact percentage in writing, which they need to file a formal complaint or negotiate with the landlord from a position of fact.
