To find the percent increase, subtract the original value from the new value, divide the difference by the original value, then multiply by 100. The formula is: Percent Increase = ((New Value − Original Value) ÷ Original Value) × 100.
For example, if a price increases from $50 to $65, the percent increase is: ((65 − 50) ÷ 50) × 100 = (15 ÷ 50) × 100 = 0.30 × 100 = 30%.
A few important notes: The original value is always the denominator—use the starting amount, not the ending amount. If your answer is negative, that indicates a percent decrease instead. The result shows how much the value changed relative to where it started, expressed as a percentage. This method works for any quantities: prices, populations, test scores, measurements, or any other values where you want to compare the change to the original amount.