Percentage Increase/Decrease Calculator: Find New Values

Percentage Increase/Decrease

Calculate the new value after applying a percentage increase or decrease to an original number. Useful for understanding price changes, growth rates, or discounts.

Original Value

The starting number or amount (e.g., 100, 50 USD)

Percentage Change

The percentage to increase or decrease by (e.g., 15 for 15%)

Operation

Choose to increase or decrease the original value

How it works

Calculate the new value after applying a percentage increase or decrease to an original number. Useful for understanding price changes, growth rates, or discounts.

The Formula

For Increase: New Value = Original Value + (Original Value × Percentage / 100)
For Decrease: New Value = Original Value - (Original Value × Percentage / 100)

Worked Example

Example: Price Change
A shirt originally costs $50. If its price increases by 20%, the new price is $50 + ($50 × 20 / 100) = $50 + $10 = $60. If it decreases by 10%, the new price is $50 - ($50 × 10 / 100) = $50 - $5 = $45.

Tips, Assumptions & Limitations

Ensure your percentage is entered as a whole number (e.g., 20 for 20%).
This tool helps you quickly see the effect of a percentage change on any starting value.
Use it for financial calculations, retail discounts, or academic problems.

FAQ

Percentage increase is the amount a value has grown, expressed as a percentage of its original amount. For example, if a price goes from $100 to $120, it's a 20% increase.

To calculate percentage decrease, you subtract the percentage of the original value from the original value. For instance, a $100 item with a 10% decrease becomes $100 - ($100 * 0.10) = $90.

Yes, this calculator is ideal for understanding price changes, calculating sales tax (increase), discounts (decrease), or estimating growth in investments (increase) over a single period.