Discount Calculator

What This Calculator Really Does

This tool prices any sale correctly: enter the original price and one or more discounts, and it shows the final price and your true savings. It handles the case shoppers get wrong most often — stacked discounts, where a second percentage applies to the already-reduced price, not the original one.

Stores quote "30% off plus an extra 20% at checkout" because the combined number sounds bigger than it is. The math says otherwise: successive discounts multiply, they never add. Seeing the two-step arithmetic side by side is the fastest way to know exactly what you will pay.

Everything runs locally in your browser. No prices, no basket data, no tracking — nothing leaves your device.

The Formula, Explained Plainly

Single discount: Final price = Original × (1 − d)

• d — the discount as a decimal (30% → 0.30). Subtracting it from 1 keeps the portion you pay.

Stacked discounts: Final price = Original × (1 − d₁) × (1 − d₂)

The second percentage always applies to the reduced price, so the order of two discounts does not change the result — but the combined saving is always smaller than the sum of the two percentages. Combined discount = 1 − (1 − d₁)(1 − d₂).

How to Use It — In Order

1. Enter the original price — the tag price before any reduction.
2. Enter the first discount — as a percentage (30, not 0.30).
3. Add a second discount if the offer stacks — most store coupons do.
4. Read the final price — what you actually pay at checkout.
5. Read the savings — both in currency and as the true combined percentage.
6. Compare offers — run a rival store's deal through the same steps to see which is genuinely cheaper.

Worked Example, Verified by Hand

A $120 jacket is 30% off, and a coupon takes an extra 20% at checkout:

1. First reduction: 120 × 0.70 = $84.00.
2. Second reduction: 84 × 0.80 = $67.20 final price.
3. Total saving: 120 − 67.20 = $52.80.
4. True combined discount: 52.80 ÷ 120 = 44% — not the 50% the two signs suggest.

If a competing store sells the same jacket for $70 flat, that deal still wins by $2.80. Stacked numbers are marketing; the final price is the only fact.

Common Mistakes to Avoid

• Adding stacked percentages — 30% + 20% is a 44% saving, never 50%, because the second cut applies to a smaller base.
• Entering decimals where percentages belong — the field wants 30, not 0.30.
• Comparing discount percentages instead of final prices — a bigger-sounding stack can still cost more than a flat price elsewhere.
• Forgetting sales tax — discounts apply to the pre-tax price in most jurisdictions, so the receipt total will be higher.
• Assuming order matters — 20% then 30% gives the same result as 30% then 20%.

Limitations

• Percentage-off pricing only — buy-one-get-one and threshold offers ("$20 off over $100") need manual conversion.
• No tax, shipping or loyalty-point adjustments — add those after the discount.
• Round-pricing rules (psychological .99 endings) are not modeled.

Expected Accuracy

Exact arithmetic at full floating-point precision, rounded for display only. The final price matches a hand calculation to the cent.

Privacy — Your Data Never Leaves This Device

The calculation runs entirely in your browser: no account, no upload, no tracking, and the page works offline after the first visit.

Related Tools & Guides

Natural next steps from Discount:

• All Finance Calculators
• Percentage Calculator — the underlying percent math
• Sales Tax Calculator — the post-discount add-on
• Markup Calculator — the seller-side view
• Guide: How to Calculate a Discount

Sources & Standards

Successive-discount arithmetic follows standard commercial percentage conventions taught in retail math.

• CFPB — consumer pricing disclosures
• FTC — pricing and advertising claims guidance

Bottom Line

Stacked discounts multiply, so the advertised sum always overstates the saving. Run the two steps here, read the final price, and compare deals on that number alone.

Frequently Asked Questions