The stacked-discount illusion
"30% off, plus an extra 20% off at checkout" reads like 50% off, and it never is. The second discount applies to the already-reduced price, so the stack lands at 44% — real money, but six points shy of what the sign implied. The calculator's total-discount line exists precisely for that sign: it converts any stack into the single honest percentage, so you can compare the deal against a plain "45% off" at the store next door.
Deal-checking habits that pay
- Judge the final price, not the percentage. A big discount on an inflated "original" price is theater; the number that matters is what leaves your account.
- Mind the tax line. Discounts shrink the sticker; tax grows the total. On big purchases the tax on the discounted price is still meaningful — the receipt shows it separately so nothing surprises you at the register.
- Selling rather than buying? Make sure your discounts still clear your costs — the margin calculator shows what a sale price does to your profit per unit.
Frequently asked
How do I calculate a discount?
Final price = original price × (1 − discount ÷ 100). A 30% discount on an $80 item: $80 × 0.70 = $56, saving you $24.
How do stacked discounts work?
They apply one after another, not added together. 30% off then an extra 20% off is not 50% off — it's $80 → $56 → $44.80, which works out to 44% total. Retailers count on the difference feeling bigger than it is.
Is tax calculated before or after the discount?
After — sales tax applies to the price you actually pay. The calculator applies your discounts first, then adds tax to the discounted amount.
What does 'up to 70% off' usually mean?
It means at least one item somewhere in the store is 70% off. Judge each item by its own final price — this calculator gives you that number faster than the shelf tag's asterisk.