What does a discount calculator actually do?
Two numbers come in: the original price and the percent off. Two numbers come out: how much you save, and what you actually pay. That's the entire job.
It sounds trivial, and the math is. The reason a calculator helps is that store signs almost never show both numbers. A tag that says "30% off $89.99" leaves you doing arithmetic in the aisle. A site that flashes "60% off everything" makes the savings sound enormous without showing the final price. Putting both on the screen at once — the dollar saved and the dollar paid — is how you tell whether the deal is good.
The Discount Calculator on this page takes the price and the percentage, gives you the sale price and the savings, and stops. No login. No email. No "sign up to see your discount." Type, press, read.
The two formulas (and why one number alone is not enough)
The math is one line each.
Savings = Original price × (Discount % ÷ 100)
Sale price = Original price − Savings
Or, in a single step:
Sale price = Original price × (1 − Discount % ÷ 100)
Worked example: an $80 item at 25% off.
- Savings: 80 × (25 ÷ 100) = 80 × 0.25 = $20
- Sale price: 80 − 20 = $60
- Or in one step: 80 × (1 − 0.25) = 80 × 0.75 = $60
The reason you want both numbers — and not just one — is that they tell different stories. "$20 off" sounds modest. "25% off" sounds aggressive. They're the same deal. Knowing both keeps the marketing language from doing your thinking for you.
How to use the Discount Calculator
Two inputs, one button.
- Enter the original price in dollars. The pre-discount price, the MSRP, the tag price — whichever number the discount is being applied to.
- Enter the discount percentage as a number from 0 to 100. Type 25 for "25% off," not 0.25.
- Press Calculate Discount.
- Read two numbers: Sale Price (what you pay) and You Save (the dollar amount of the discount).
The calculator validates that the percentage is between 0 and 100. "110% off" doesn't mean the store pays you; it means someone typed the wrong number, and the calculator quietly refuses to produce a misleading answer.
Common discount percentages: what they actually save
The table covers the percentages you'll see most often on price tags and emails. A useful trick: 10% off is the price with one digit chopped off the end (kind of). 50% off is half. 25% off is a quarter. Most of the rest you'll want a calculator for, which is why this one exists.
| Original price | 10% off | 20% off | 25% off | 30% off | 50% off | 70% off |
|---|---|---|---|---|---|---|
| $20 | $18.00 | $16.00 | $15.00 | $14.00 | $10.00 | $6.00 |
| $50 | $45.00 | $40.00 | $37.50 | $35.00 | $25.00 | $15.00 |
| $80 | $72.00 | $64.00 | $60.00 | $56.00 | $40.00 | $24.00 |
| $100 | $90.00 | $80.00 | $75.00 | $70.00 | $50.00 | $30.00 |
| $150 | $135.00 | $120.00 | $112.50 | $105.00 | $75.00 | $45.00 |
| $250 | $225.00 | $200.00 | $187.50 | $175.00 | $125.00 | $75.00 |
| $500 | $450.00 | $400.00 | $375.00 | $350.00 | $250.00 | $150.00 |
Two patterns worth noticing. First: the dollar amount of a percentage discount scales linearly with the price. 25% off $50 is $12.50; 25% off $500 is $125. The percentage is the same; the dollars get serious fast. Second: discounts above 50% are unusual outside of clearance and don't always mean what they look like — see the next section.
Stacked discounts: 20% off, then another 20%, is not 40% off
This is the single most common discount-math error, and stores rely on it. When a coupon stacks on top of an existing sale, the second percentage is applied to the already-reduced price, not the original.
Worked example: a $100 item, 20% off on the tag, plus a 20% coupon at checkout.
- First discount: $100 × (1 − 0.20) = $80
- Second discount: $80 × (1 − 0.20) = $64
- True combined discount: ($100 − $64) ÷ $100 = 36%, not 40%
The general formula for two stacked discounts is:
Combined discount = 1 − (1 − d₁) × (1 − d₂)
For three or more, keep multiplying the (1 − d) factors. Two 25% discounts stacked = 1 − (0.75 × 0.75) = 43.75%, not 50%. Three 30% discounts stacked = 1 − (0.70³) = 65.7%, not 90%. The gap grows with the size of each individual discount.
Order doesn't matter for the math — 20% off then 30% off gives the same final price as 30% off then 20% off. But it matters for the way stores advertise. A "30% off + extra 20%" sign sounds bigger than a "44% off" sign, even though they're the same deal. The Discount Calculator handles one discount at a time; for stacked deals, run it twice (first on the original, then on the result).
Discount vs markdown vs markup (they're not interchangeable)
Retail and finance use three related but distinct percentage terms. Mixing them up makes you misjudge deals.
- Discount — a percentage off a price. The calculator's job. "$100 with 25% off = $75."
- Markdown — a reduction from a previous retail price. Often used by stores to clear inventory. Numerically the same as a discount when applied to a sticker price, but it's a store-side term ("we marked this down 40%") rather than a customer-side one ("I got 40% off").
- Markup — the opposite direction. The percentage added to a cost to set the retail price. A $40 item marked up 50% sells for $60, not $80. Markup percentages and discount percentages don't cancel out: a 50% markup followed by a 50% discount lands at $30, not back at the original $40.
The Discount Calculator handles discounts and markdowns (same math). For markup, you'd want the Percentage Calculator or a dedicated markup tool.
"Original price" deserves a small dose of skepticism
The math is honest. The "original price" sometimes isn't. Three common patterns:
The phantom MSRP. Some products are sold exclusively at "sale" prices, with an "original" or "MSRP" number that nobody has ever actually paid. Furniture, mattresses, jewelry, and direct-to-consumer brands are repeat offenders. If "60% off $1,200" is what every store charges every day of the year, the real price is the sale price; there's no discount to speak of.
The pre-sale markup. Some stores raise prices in the weeks before a known sale event (Black Friday, Memorial Day) so the discount looks larger. The genuine year-round price might be $80; the price goes up to $120 in October; then the "33% off" Black Friday deal brings it back to $80. The price-tracking sites like CamelCamelCamel and Honey exist mostly to catch this pattern.
The bundled "savings." "Save $150 when you buy this $1,000 laptop with this $50 mouse" is a sentence designed to make you think you saved $150. You saved $50 (the mouse price) on something you might not have bought otherwise. The Discount Calculator works on a single item; bundle math needs item-by-item review.
The calculator computes what the percentage says it should compute. Whether the original price is real is a question the math can't answer — but you can, with a price history check or a quick search.
Working backward: I paid $X for an item marked $Y, what was the discount?
This is the inverse problem, and it's worth knowing.
Discount % = ((Original − Sale) ÷ Original) × 100
Worked example: a jacket marked $120, you paid $84.
- Savings: 120 − 84 = $36
- Discount %: (36 ÷ 120) × 100 = 30%
Useful for checking whether a "30% off!" sign is accurate after taxes and fees get added at checkout (it often isn't, because percentage discounts apply to the pre-tax subtotal — sales tax is added afterward to the discounted price, not the original).
Related calculations
The Discount Calculator answers one question. These tools handle adjacent ones:
- Percentage Calculator — works for any "what percent of X is Y" question, including discount math run in either direction.
- VAT Calculator — for prices that include or exclude value-added tax, which interacts with discount math in non-trivial ways (the order of operations matters).
- Percent Off Calculator — a near-identical sibling to this one, kept separate because some search engines treat "discount" and "percent off" as different queries.
- Savings Calculator — for projecting what you'd accumulate by investing the dollar amount of a discount instead of spending it. A useful exercise for big-ticket items.
Frequently asked questions
Why does the calculator give a final price and a savings number? Isn't one enough?
Both numbers are useful at the moment of decision. The final price tells you what hits your card. The savings tells you how much the discount is worth in absolute terms. A 30% off a $20 item saves $6 — fine, but not life-changing. A 30% off a $1,200 item saves $360 — a different conversation. Showing both keeps the percentage from feeling bigger or smaller than the dollars warrant.
Does the calculator include sales tax?
No. The calculator computes the pre-tax discount, which is how stores apply percentage discounts: to the pre-tax subtotal. Sales tax is then added on top of the discounted price. If you want the total out-of-pocket including tax, run the discount first, then multiply the result by (1 + tax rate). For an 8% sales tax: discounted price × 1.08.
What if the discount is larger than the price?
The calculator caps the discount input at 100% (no negative final prices). If you typed a percentage above 100, you'd get a sale price of zero, which is not a real-world outcome — even a clearance item below cost isn't free. If you see "100% off" on a sign, it's almost always a sign error or a promotional gift with purchase, not a free item.
Can I use this for tip calculations?
Tips are percentages of a price, so the math works, but the direction is opposite — you're adding a percentage rather than subtracting. To use the Discount Calculator for tips, calculate the tip amount on a 0% discount of the subtotal (which won't give you what you need) — or just use the Percentage Calculator or a dedicated tip calculator. Wrong tool, right neighborhood.
How do I calculate the discount on a buy-one-get-one (BOGO) deal?
A true BOGO ("buy one, get one free") is a 50% discount on the total of two items. If the items are different prices, the freebie is typically the cheaper one, which makes the effective discount less than 50%. Worked example: a $40 shirt and a $20 shirt, BOGO-free → you pay $40 for both, which is a $60 - $40 = $20 savings out of $60, or 33%. "Buy one, get one half off" is 25% on the total when the items are the same price. Stores love BOGO because the math looks better than it is.
The store's "$50 off" sign — how do I convert that to a percentage?
Run the inverse formula: (savings ÷ original price) × 100. $50 off a $200 item = 25%. $50 off a $500 item = 10%. Fixed-dollar discounts look the same in the window but have very different percentage impacts depending on the price tier they're attached to.
Why don't percentage discounts always feel as big as they sound?
Two reasons. First: percentages of small numbers are small numbers. 20% off a $15 item is $3 — technically a discount, practically a coupon for a cup of coffee. Second: percentages above 50% start to compound oddly because the base shrinks. Going from 50% off to 60% off on a $100 item only saves an extra $10, not a proportional jump. After about 70% off, the marginal additional savings get small. The biggest absolute dollar savings usually live in the 20-40% off range on expensive items, not the 70%+ range on clearance.
Is "up to X% off" a useful number?
Rarely. "Up to 70% off" means at least one item in the store is at 70% off; the rest could be at 5%. The phrase is calibrated to the maximum, not the average. If a percentage looks impressive in marketing copy, the question to ask is which items are at that percentage and whether they're items you'd want at any price. The Discount Calculator works on actual prices, not promotional copy — type in what's on the tag for the thing you're actually buying.