About the Discount Calculator
Finds savings and final price, or reverses from a sale price, with correct stacked-discount compounding.
What it is
Three modes: standard (price + discount → savings and final price), reverse (final price + discount → original price), and stacked (a chain of successive discounts, each applied to the already-reduced price).
Why stacking matters
A common mistake is adding stacked percentages together (20% + 10% = 30%). Each discount actually applies to the running price, so 20% then 10% off $100 gives $100 × 0.8 × 0.9 = $72, not $70. The calculator shows the running price after each step.