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Finance

Discount Calculator (Sale Price & Savings)

Calculate sale price after percentage discount, or work out the original price from a sale price. Handles stacked discounts too.

Sale price
$150.00
You save
$50.00
Effective off
25.0%

What this calculates

Sales advertising is designed to confuse: 30 % off plus an extra 20 %, original price was X — wait, what does this actually cost? This calculator handles the three common cases: apply a discount to a price, work out the original price from a sale price, and stack two discounts properly (they don't simply add up).

Formula & how it works

Sale price = price × (1 − discount/100). Savings = price × discount/100. Reverse: original = sale ÷ (1 − discount/100). Stacked discounts: final = price × (1 − d1/100) × (1 − d2/100). Note: 30 % then 20 % = 1 × 0.7 × 0.8 = 0.56 = 44 % total off, not 50 %.

Worked example

A $200 item marked 25 % off. Sale price = 200 × 0.75 = $150. Savings = $50. With an extra 15 % loyalty discount on top: 150 × 0.85 = $127.50. Total effective discount = (200 − 127.50) / 200 = 36.25 %, not 40 %.

Frequently asked questions

Why don't stacked discounts add up?

Each is applied to a smaller base. 30 % off $100 = $70. Another 20 % off the new $70 = $56, not $50. The second discount only applies to what's left after the first.

How are 'buy one get one' deals calculated?

BOGO 50 % off = effectively 25 % off both items. BOGO free = 50 % off both items. The math is averaged across the bundle.

What about coupon codes that apply to subtotals?

If the code applies to pre-tax subtotal, it lowers what tax is calculated on too. If it applies after tax, the savings are smaller. Check at checkout.

Are 'compare at' prices real?

Often inflated. Outlet stores notoriously show 'compare at' prices that the item never actually sold for at retail. Trust real-world pricing, not the manufacturer's suggested ceiling.

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