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About

Retailers, investors, and shoppers use percentage change calculations to quantify price volatility or margin adjustments. This tool isolates the relative difference between an initial value and a final value. Accurately determining these percentages is critical for setting profit margins in retail or tracking asset performance in finance. A common error involves confusing markup (based on cost) with margin (based on revenue). This utility focuses strictly on the mathematical delta between two price points, handling both positive growth and negative corrections (discounts) with high decimal precision.

percentage change discount calculator markup calculator inflation price difference

Formulas

The standard formula for percentage change Δ% compares the difference relative to the starting value Vold.

Δ% = Vnew VoldVold × 100

When applying a known percentage P to find a new price:

Vnew = Vold × (1 + P100)

Reference Data

ScenarioOld PriceNew PriceFormula Result
Price Hike100150+50%
Discount1007525%
Doubling50100+100%
Total Loss1000100%
Inflation1.001.03+3%
Reversal100 150150 10033.3%

Frequently Asked Questions

Percentages are relative to the starting number. Going from 100 to 50 is a 50% loss. Going from 50 back to 100 is a 100% gain, because the baseline (denominator) is smaller in the second case.
Mathematically yes, but in most retail contexts, negative prices (paying someone to take an item) are rare. In finance (e.g., oil futures), negative inputs are valid.
To add 20% tax, enter the Pre-Tax Price as "Old" and use the "Forward" calculation with +20%. Or simply multiply by 1.20.
One basis point is 0.01%. This tool calculates standard percentage. To convert to basis points, multiply the result by 100.