Discount Calculators

DiscountLab guides

Plain-language answers to discount calculators questions, written from the same sourced data behind DiscountLab. Every guide lists its sources and the date it was last updated.

• Updated June 10, 2026

  Is 20% off plus 10% off the same as 30% off?

  No. Stacked discounts multiply, not add. Two sequential percentage discounts always produce a smaller saving than their sum suggests.