How to Calculate Sale Prices
The formula is simple: Sale Price = Original Price x (1 - Discount%/100). A $100 item at 25% off: $100 x 0.75 = $75. Your savings: $25.
Stacking Discounts
When stores offer "25% off plus an additional 10% off," these discounts stack multiplicatively, not additively. A $100 item: first 25% off = $75, then 10% off $75 = $67.50. That's 32.5% total savings, not 35%. Always calculate each discount sequentially.
Sales Tax Consideration
Sales tax is calculated on the discounted price, not the original. If your state charges 8% tax on a $75 sale item: $75 x 1.08 = $81. You don't pay tax on the $25 discount.
Frequently Asked Questions
What is 25% off $100?
$100 x 0.25 = $25 discount. Sale price: $75. With 8% tax: $81.
How to find original price from sale price?
Divide sale price by (1 - discount%). If an item is $60 after 25% off: $60 / 0.75 = $80 original price.
What's my state sales tax?
Rates vary by state: California 7.25%, Texas 6.25%, New York 4% (plus local), Florida 6%. Five states have no sales tax: Oregon, Montana, New Hampshire, Delaware, Alaska.
Is a "buy one get one 50% off" deal really 25% off?
Yes! If both items cost the same, you're getting 25% off the total. BOGO 50% on two $40 items: you pay $60 instead of $80 = 25% savings.