Discount Calculator with Sales Tax

About the Discount Calculator

Whether you are shopping during Black Friday clearance sales, budgeting with promo codes, or factoring in local sales tax, our Discount Calculator gives you total financial clarity.

Unlike rigid calculators that only work in one direction, this versatile tool allows you to provide any 2 values among Original Price, Discount %, Sale Price, and Amount Saved. Enter any two known figures, and the calculator instantly solves the remaining unknowns!

Core Discount & Retail Formulas

Discount arithmetic is governed by four interconnected variables:

How to Calculate Discounts in Any Direction

1. Standard Discount (% Off): Convert the discount percentage into a decimal (e.g. 20% = 0.20), multiply by the original price to find the dollar savings, and subtract that amount from the original price.
2. Reverse Discount (Find Original Price): If an item is on sale for $80 after a 20% discount, subtract 20% from 100% to get 80% (0.80). Divide the sale price by 0.80 to reveal the original price: $80 ÷ 0.80 = $100.
3. Find the Discount Rate (%): Subtract the sale price from the original price to find your savings, divide by the original price, and multiply by 100.
4. Stacked / Extra Coupons: Consecutive discounts apply sequentially. If an item has 40% off plus an extra 10% coupon, the 10% is deducted from the 40%-reduced price, not the original sticker price.

Worked Example: For a $50 item with 20% off: You save $50 × 0.20 = $10, making the final sale price $50 − $10 = $40.

Frequently Asked Questions (FAQ)

Can I find the original price if I only know the sale price and discount percentage?

Yes! Divide the sale price by (1 − Discount% / 100). For example, if you paid $75 after a 25% discount, divide $75 by 0.75 to find the original $100 price.

How do stacked discounts (e.g., 50% off + extra 20% coupon) work?

Stacked discounts apply successively rather than adding together. A $100 item at 50% off drops to $50; the extra 20% off then takes $10 off the $50 price, resulting in a final price of $40 (a total 60% savings, not 70%).

Is sales tax applied before or after the discount?

In virtually all retail jurisdictions, sales tax is calculated on the final discounted price that you actually pay at checkout, not the original pre-discount sticker price.