Percentage Increase and Decrease
7 min read · Updated September 26, 2026 · by the SolveCalcPro editorial team
Prices go up, populations fall, grades improve. Percentage change measures how much something has gone up or down compared with where it started. It is one of the most useful everyday maths skills, and a source of many common mistakes.
The formula
Percent change = (new − old) ÷ old × 100. A value rising from 80 to 92 is (92 − 80) ÷ 80 × 100 = +15%. One falling from 250 to 200 is (200 − 250) ÷ 250 × 100 = −20%. The percentage change calculator does it instantly.
Increasing or decreasing by a percent
Multiply by (1 + rate) to increase and by (1 − rate) to decrease. A price of $40 up 15% is $40 × 1.15 = $46. A price of $40 down 15% is $40 × 0.85 = $34.
Reversing a change
To find the original, divide by the multiplier. If a price is $150 after a 25% rise, the original was 150 ÷ 1.25 = $120. Do not subtract 25% from 150, which gives 112.50.
Successive changes
Changes multiply. Up 10% then down 10% is 1.1 × 0.9 = 0.99, a 1% loss overall. And a fall of 20% followed by a rise of 20% leaves you at 0.8 × 1.2 = 0.96.
Markup versus margin
If an item costs $60 and sells for $90, the profit is $30. The markup is 30 ÷ 60 = 50% of cost. The margin is 30 ÷ 90 = 33.3% of the selling price. They describe the same profit in different ways, so always check which is meant.
A real example: prices
If a $4.00 item now costs $4.60, the rise is 0.60 ÷ 4.00 = 15%. Learn more percentage skills in how to calculate percentages, and try the discount calculator.
Practice questions
Test yourself, then tap to check. Answers are calculated by the tools linked below.
- A rent rises from $1,200 to $1,320. What is the percent increase?
Show answer
Percent change: +10%
- A $150 jacket is 30% off with an extra 10% coupon and 7% tax. What is the total?
Show answer
Sale price (before tax): $94.50
- What is 35% of 240?
Show answer
35% of 240: 84
Frequently asked questions
How do I calculate percentage increase?
(new − old) ÷ old × 100.
Why is a 50% rise followed by a 50% fall a net loss?
The fall applies to a larger number. 100 → 150 → 75.
What is the difference between markup and margin?
Markup is profit as a percentage of cost; margin is profit as a percentage of the selling price.
How do I find the original price after a discount?
Divide the sale price by (1 − discount rate).
Try it yourself
Percentage Change CalculatorFind the percent increase or decrease between two numbers.Discount CalculatorWork out the sale price, the savings and the final total with tax after one or two discounts.Percentage CalculatorFind a percent of a number, percent change, and increases or decreases.Keep learning
How to Calculate Percentages7 min read
How Compound Interest Works7 min readConverting Fractions, Decimals and Percents8 min readWritten and reviewed by the SolveCalcPro editorial team. Spot a mistake? Tell us. See our editorial policy.