How to Calculate Percentage Increase

A percentage increase measures how much a value has grown, expressed as a percentage of where it started. It is always measured against the original value, not the new one — that is the most common source of mistakes.

You might use it for a price rise, a pay increase, growth in sales or subscribers, or any situation where something has gone up and you want to know by how much in relative terms.

Percentage Increase = ((New Value − Original Value) ÷ Original Value) × 100

Three steps:

• Subtract the original value from the new value to find the amount of the increase.
• Divide that increase by the original value so it is measured against the starting point.
• Multiply by 100 to turn the fraction into a percentage.

Sometimes you want to go the other way — start from a number and add a percentage to it. Turn the percentage into a multiplier by adding 1 to (percentage ÷ 100), then multiply:

New Value = Original Value × (1 + Percentage ÷ 100)

To add 15% to £80: £80 × 1.15 = £92. This is exactly what the price increase calculator does for money amounts.

Percentage increase is specifically for values that have gone up. Percentage change covers both increases and decreases in one figure — a positive result is an increase, a negative one a decrease. Percentage difference compares two values without treating either as the starting point, using their average as the base. See our percentage change guide for more on how these differ.

• Dividing by the new value. Always divide by the original. A rise from £80 to £92 is 12 ÷ 80, not 12 ÷ 92.
• Forgetting increases can exceed 100%. If a value more than doubles, the increase is over 100% — that is correct, not an error.
• Confusing increase with change. If the value might have fallen, use percentage change instead so the sign tells you the direction.

Enter your two values into the percentage increase calculator to see the result and the full working instantly.