Discount Calculator

Discount inputs

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$
%
Have a promo like “Buy 1, get 30% off 1 item”?

Results

Enter values to see results.
Quick Jump:🧾 How it works🏷️ Deal types🧮 Formulas⚠️ Pitfalls❓ FAQs

How this discount calculator works

This calculator is designed for real shopping scenarios. Pick a deal type (percent off, fixed amount off, buy X get Y, or stacked discounts), enter the unit price, and the calculator shows your final price, total savings, and effective discount.

Deal types covered

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Percent off

Sale price = Unit price × (1 − discount%/100). Also supports promos like “Buy 1, get 50% off the next item”. If item prices vary, many stores apply this promo to the lowest-priced eligible item.

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I know what I pay

If nothing matches your promotion exactly, enter the original price and the final price you pay. The calculator will show savings and the effective discount %.

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Cart items

Add multiple cart lines (qty, unit price, discount %) to compute total savings and the effective discount across the whole cart.

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Fixed amount off

Sale price = max(0, Unit price − amount off).

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Buy X get Y

Calculates how many items you pay for vs get free, then shows the effective unit price and totals.

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Stacked discounts

Applies multiple percent discounts sequentially (e.g., 20% then 10% is not the same as 30% off).

Formulas & worked examples

These are the same calculations used in the tool. Use the examples to sanity-check a deal before checkout.

Percent off (simple)

sale = price × (1 − d/100)

Example: price 1,449, discount 15% → sale = 1449 × (1 − 0.15) = 1,231.65

Fixed amount off

sale = max(0, price − off)

Example: price 999, off 200 → sale = 799

Stacked % discounts

final = price × Π(1 − di/100)
(multiply one discount after another)

Example: 20% then 10% on 1,000 → 1000 × 0.8 × 0.9 = 720 (effective 28% off)

Buy X get Y (free items)

pay_items = sets × X
total_items = sets × (X + Y)
effective_unit = (pay_items × price) / total_items

Example: Buy 2 get 1 free (X=2, Y=1), price 300 → effective unit = (2×300)/3 = 200

Effective discount ("I know what I pay")

savings = original − final
effective% = (savings / original) × 100

Example: original 2,000, final 1,499 → savings 501 → effective% = 501/2000×100 = 25.05%

Common deal tricks & pitfalls (what to watch for)

Retail promotions can be worded in ways that look better than they are. These are common patterns — not every store does them, but it’s worth checking.

"Up to" discounts

"Up to 70% off" often means only a few items are 70% off. Check the exact item discount.

Inflated list price

A big percent off is less impressive if the "original" price is higher than usual market price.

BOGO on mixed prices

"Buy 1 get 1" is strongest when items are the same price. If prices vary, the free/discounted item may be the cheapest.

Minimum spend & exclusions

Coupons may require a minimum cart total, exclude brands, or apply only to specific categories.

Stacking order matters

"Extra 10% off" might apply after other discounts, not on the original price. Stacked discounts are multiplicative.

Shipping, taxes, fees

A discount can be offset by delivery fees or add-ons. Compare the final amount you actually pay.

❓ Frequently Asked Questions

How do I calculate percent off?▼
Sale price = Unit price × (1 − discount% / 100).
What’s the difference between discount percent and discount amount?▼
Discount amount is how much you save in money. Discount percent is that savings relative to the original price.
How do stacked discounts work?▼
Stacked discounts apply one after another. Example: 20% then 10% means you pay 80% of the original, then 90% of that, so you pay 72% overall (an effective 28% discount).
How do I compare Buy X Get Y deals to a percent-off sale?▼
Use the Buy X Get Y mode to see the effective unit price and effective discount. You can then compare that effective discount to a straight percent-off offer.
What’s the difference between discount percent and effective discount?▼
Discount percent is the rate you apply (like 20% off). Effective discount compares the final price to the original price and expresses the savings as a percent.
Can this calculator handle multiple items?▼
Yes. Use Quantity for simple percent/fixed/stacked discounts, or use Deal sets for Buy X Get Y bundles.