Discount Calculator

How to use the discount calculator

1. Enter the Original price — the full price before any reduction.
2. Enter the Discount percentage shown on the tag or in the cart.
3. Add a Second discount only if the promotion stacks (for example an extra 10% at checkout).
4. Read the final price and the money saved. Anything you change recalculates immediately.

Worked example

A jacket listed at $120 with 25% off drops to $90, a saving of $30. With an extra 10% at checkout the price becomes $81 — the total saving is $39, an effective 32.5% off, not 35%.

The discount formulas

Sale price = Original × (1 − rate) · Saving = Original × rate

Stacked price = Original × (1 − r₁) × (1 − r₂)

Stacked discounts are not added

25% then 10% is not 35% off. The second discount applies to the already-reduced price, so the effective rate is 1 − (0.75 × 0.90) = 32.5%. Retailers lean on this gap: "extra 10% off" sounds bigger than it is.

Working backwards

If you know the original and the sale price, the rate is (Original − Sale) ÷ Original. A $120 item selling at $90 is 30 ÷ 120 = 25% off — handy for checking a claim at the till.

Discounts worth pausing over

• "Up to 70% off" — the headline rate applies to a handful of items. Check the tag on the thing you actually want.
• Percent off vs dollars off — on cheap items a flat $10 beats 20%; on expensive ones the percentage wins. Run both.
• Bundle the stack correctly. A coupon and a sale usually multiply, but some retailers add them. The difference is real money.
• Watch the reference price. A "50% off" tag on an inflated original price is not a saving at all.
• Compare the final price, not the rate. Two stores, two rates — the lower final number is the better deal.