S Subtract/Add
% Discount Calculator
Calculate sale prices, savings, and final cost after discount. Optionally add sales tax for the true checkout price.
How to Use the Discount Calculator
Fill in the fields above and click calculate. All calculations run instantly in your browser — no data is sent anywhere.
Frequently Asked Questions
How is the discount calculated?
Sale Price = Original Price × (1 − Discount% ÷ 100). This is the S (Subtract) step in GEMS.
Can I add sales tax?
Yes — enter your local sales tax rate and get the final price after both discount and tax.
What if I know the sale price and want the discount percent?
Use the Percentage Calculator: ((Original − Sale) ÷ Original) × 100 = Discount%.