Percentage Increase/Decrease Calculator

About the Percentage Increase/Decrease Calculator

Percentage Increase/Decrease Calculator is two tools in one: compare two numbers to see the percentage jump (or drop) between them, or apply a known percentage to a base number to find the new value.

How to use

1. In the top row, enter the original value and the new value to see the percentage change.
2. In the bottom row, enter a base value and a percentage (positive or negative) to apply it.
3. Results appear in the output panel with direction and a short explanation.

Benefits & key features

• Handles both directions (increase and decrease) in a single tool.
• Shows the raw difference alongside the percentage — useful for financial work.
• Edge-case safe (zero original, negative bases) with clear error messages.
• Ideal for sales growth, investment returns and exam-score tracking.

Pro tip

When comparing sales year-over-year, a 50% drop followed by a 50% rise does NOT return to the original number — this tool makes that truth obvious.

Why choose toolsfy for Calculators tools?

A good calculator should give you a defensible number you can paste into a spreadsheet, not a vague range behind a paywall. toolsfy's calculators show every formula, every step and every input so you can trust the result — and cross-check it. Because the math runs in your browser, there is no latency, no rate limit, and no risk of a server returning a cached, stale, or rounded answer.

Common use cases

• Engineering students verifying textbook answers on the bus, without burning mobile data on a heavyweight scientific-calculator app.
• Freelancers converting between units in client briefs — millimetres to inches, pounds to kilograms, US fluid ounces to millilitres — in seconds.
• Shopkeepers calculating the effective percentage change in margins after a supplier price hike, without firing up Excel on a point-of-sale tablet.

Frequently asked questions