Percentage Increase Calculator
Work out how much a value has grown in percentage terms — for prices, salaries, traffic or any pair of before-and-after numbers.
How to use it
- Enter the original value, then the new value.
- The result is positive for a rise and negative if the value actually fell.
- Use the ratio tile to see the change as a multiplier instead.
Examples
| Salary 40,000 → 46,000 | +15% |
| Price 250 → 300 | +20% |
Percentage increase is the everyday version of the calculation behind a pay rise, a rent hike or a price rise notice: how much bigger did the new figure get, expressed as a share of the original. Enter the old and new values and the tool gives you the rise in the direction you actually care about, without you having to remember which number goes on the bottom.
Going the other way — adding a known percentage
If you already know the percentage and want the new value, multiply the original by (1 + percentage ÷ 100). A 40,000 salary with a 15% raise becomes 40,000 × 1.15 = 46,000 — the exact reverse of the calculation this tool performs.
Where this comes up
- Salary negotiations — checking whether an offered raise matches what was promised in percentage terms.
- Retail pricing — confirming a 'up to 20% more' claim against the actual before-and-after price.
- Rent reviews and utility bills, where increases are usually quoted as a percentage of the previous rate.
Questions people ask
How do I add a percentage increase to a number?
Multiply by (1 + percentage ÷ 100). To add 15% to 40,000: 40,000 × 1.15 = 46,000.
Is anything sent to a server?
No. Every calculation runs in your browser, so nothing you type is uploaded and the page keeps working offline once it has loaded.
Last updated 17 August 2026