Percentage Change Calculator
Work out the percentage change between an original value and a new value. The result shows whether it is an increase or a decrease, with the amount of change and the full working. Use it for prices, sales, costs or any two figures where you want a single percentage that covers both directions.
A positive result is an increase; a negative result is a decrease. The same formula covers both directions.
The percentage change formula
Percentage Change = ((New Value − Original Value) ÷ Original Value) × 100
- Subtract the original value from the new value. A positive number means the value went up; a negative number means it went down.
- Divide that difference by the original value so the change is measured against where you started, not where you ended up.
- Multiply by 100 to turn the result into a percentage. A positive result is an increase; a negative result is a decrease.
How to use this calculator
- Enter the original value you are starting from.
- Enter the new value you are comparing it to.
- The percentage change, direction and amount of change appear instantly.
Worked examples
A price changing from one amount to another
A product rises from £80 to £92. Change = 92 − 80 = 12. Percentage change = 12 ÷ 80 × 100 = 15%. The price went up 15% — a positive result, so it is an increase.
Sales increasing
Monthly sales climb from £15,000 to £18,000. Change = 18,000 − 15,000 = 3,000. Percentage change = 3,000 ÷ 15,000 × 100 = 20%. Sales grew 20%.
Costs decreasing
A supplier bill falls from £250 to £210. Change = 210 − 250 = −40. Percentage change = −40 ÷ 250 × 100 = −16%. The negative result means costs fell by 16%.
A value falling and producing a negative percentage change
A meter reading drops from 4,641 to 4,200. Change = 4,200 − 4,641 = −441. Percentage change = −441 ÷ 4,641 × 100 = −9.5%. The minus sign confirms it is a 9.5% decrease.
A change over 100%
A newsletter list grows from 400 to 920. Change = 920 − 400 = 520. Percentage change = 520 ÷ 400 × 100 = 130%. The list more than doubled, so the percentage change is over 100%.
Percentage change, increase, decrease and difference
These four are easy to mix up. Here is the difference, in plain English.
- Percentage change
- A single figure that covers both directions — a positive result is an increase, a negative result is a decrease. Use it when you have an original and a new value and want one number for the move.
- Percentage increase
- Specifically for values that have gone up. The maths is the same, but the result is expected to be positive. Use the percentage increase calculator when you know the direction is a rise.
- Percentage decrease
- Specifically for values that have gone down. Use the percentage decrease calculator when you know the direction is a fall, such as a discount or depreciation.
- Percentage difference
- Compares two values without treating either as the starting point. It uses the average of the two as the base, so it is useful when neither number is clearly the original.