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Percentage Change Calculator

Find the percentage difference between any two values — works for both increases and decreases.

🔄 Percentage Change Calculator MAIN TOOL

% Change = ((New − Old) ÷ |Old|) × 100
Result
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Related Percentage Tools

📈 Percentage Increase Calculator 🏷️ Discount Calculator 🔢 % of a Number Calculator 📊 All Percentage Tools (Hub)

How Do You Work It Out?

Percentage change = (new value − old value) ÷ old value × 100. A positive answer is an increase and a negative one a decrease: 10,000 visitors falling to 8,500 is a −15% change. Enter the old and new values above to get the change instantly, whichever direction it goes.

Quick Reference

FromToChange
100150+50%
150100−33.3%
80100+25%
10,0008,500−15%
4552.20+16%
20050−75%

The Percentage Change Formula

% Change = ((New Value − Original Value) ÷ |Original Value|) × 100

A positive result means an increase; a negative result means a decrease.

Worked Example — Decrease

If website traffic dropped from 10,000 visitors to 8,500: ((8,500 − 10,000) ÷ 10,000) × 100 = −15% (a 15% decrease).

Worked Example — Increase

If a stock price moved from $45 to $52.20: ((52.20 − 45) ÷ 45) × 100 = 16% (a 16% increase).

Common Uses for Percentage Change

This calculation applies broadly: comparing month-over-month business metrics, tracking weight change, measuring stock or investment performance, comparing exam scores across attempts, or any scenario where you're evaluating how much something has moved between two points.

A Common Misunderstanding: Percentage Change Isn't Symmetric

Going from 100 to 150 is a 50% increase. But going from 150 back to 100 is not a 50% decrease — it's a 33.3% decrease, since the base value used in the calculation changes. This asymmetry trips people up often: always be clear about which value is your "original" and which is your "new" when interpreting a percentage change.

Worked Example — Negative Values

The formula still works when the original value is negative, as long as it isn't zero. Say a small business's net income improved from a $50,000 loss to a $20,000 loss: ((−20,000 − (−50,000)) ÷ |−50,000|) × 100 = (30,000 ÷ 50,000) × 100 = 60% increase, meaning the loss shrank by 60%, even though both figures are negative.

For raises and price rises specifically, see the percentage increase calculator; to undo a percentage, use the reverse percentage calculator. See every tool in the percentage calculator hub.

How to Use the Percentage Change Calculator

  1. Enter the original (old) value.
  2. Enter the new value.
  3. Read the percentage change: positive is an increase, negative is a decrease.
  4. Swap the two numbers to see why a 25% rise is not undone by a 25% fall.

How the Percentage Change Calculator Saves You Time

Percentage change is (new − old) ÷ old × 100, and it is easy to divide by the wrong number. Enter the two values and the right answer appears.

Frequently Asked Questions

How do I calculate percentage change?

Subtract the old value from the new value, divide the result by the old value, then multiply by 100. For 10,000 falling to 8,500: (8,500 − 10,000) ÷ 10,000 × 100 = −15%. A positive result is an increase and a negative result is a decrease.

What is percentage difference, and how is it different?

Percentage difference compares two values when neither is the starting point, such as two shop prices. Divide the gap between them by their average and multiply by 100: for 40 and 60, 20 ÷ 50 × 100 = 40%. This calculator gives percentage change, which uses the old value as the base.

Why isn't percentage change symmetric between two values?

Because the formula always divides by the original value, not the new one. Going from 100 to 150 is a 50% increase, but going back from 150 to 100 is only a 33.3% decrease — the base value changed.

What's the difference between this and the Percentage Increase Calculator?

Both use the same formula. This page is framed as a general-purpose tool for any comparison (increase or decrease), while the Percentage Increase Calculator is framed specifically around growth scenarios like raises and price increases.

What if my original value is zero?

Percentage change is undefined when the original value is zero, since you cannot divide by zero. In that case, describe the change in absolute terms instead of as a percentage.

Can I calculate percentage change when the original value is negative?

Yes, as long as it isn't zero. The formula uses the absolute value of the original number as the base, so it still works correctly. For example, a net income improving from a $50,000 loss to a $20,000 loss is a 60% increase: ((−20,000 − (−50,000)) ÷ |−50,000|) × 100 = 60%.

What's the difference between a percentage change and a percentage point change?

A percentage point change is the plain difference between two percentages. A percentage change (or increase/decrease) expresses that same difference relative to the starting value. A rate moving from 4% to 6% is a 2 percentage point change, but a 50% relative change, since (6 − 4) ÷ 4 × 100 = 50%.

Last updated: September 2026

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