1. 01Choose the Discount, Reduction %, Spend & save or Reverse mode.
2. 02Enter the original price, then fill in the matching discount in tenths, reduction percentage, spend threshold or current price.
3. 03For spend-and-save, follow the promotion rules to decide whether to switch on “stack once per full threshold”.
4. 04Read the final price, the amount saved and the equivalent discount / percent off.

Discount range

— the discount must be greater than 0 and at most 10 on the tool's tenths scale (8.5 means you pay 85%, i.e. 15% off); the flat reduction percentage runs from 0–100.

Prices

— the original price must be non-negative; in reverse mode it must be greater than 0, and the current price may be 0 or above the original.

Spend and save

— the threshold must be greater than 0 and the reduction cannot be negative; the number of repeats is floor(original price / threshold).

Scope

— the tool only does arithmetic on the offer rules you enter; it knows nothing about store-coupon exclusions, member prices, shipping, taxes or payment discounts.

What it does not do

— it does not scrape product prices, compare historical prices on shopping platforms or judge whether a promotion is worth buying.

Prices and offer details are calculated only in your browser; nothing is saved or uploaded.