Financial · Live
Percent Off Calculator —
sale price & reverse lookup.
Find the final sale price from any original price and discount percentage or work backwards to find the original price from a sale price. Instant visual savings bar, multi-price reference table, and optional sales tax, all updating live as you type.
Inputs
Your deal
Sales tax
Optional- Original
- $100.00
- You save
- $25.00
- Sale price
- $75.00
Sale price
25% off
You save $25.00 off $100.00
Reference
25% off, across common prices
| Original price | Sale price | You save |
|---|---|---|
| $5.00 | $3.75 | $1.25 |
| $10.00 | $7.50 | $2.50 |
| $20.00 | $15.00 | $5.00 |
| $25.00 | $18.75 | $6.25 |
| $50.00 | $37.50 | $12.50 |
| $75.00 | $56.25 | $18.75 |
| $100.00 | $75.00 | $25.00 |
| $150.00 | $112.50 | $37.50 |
| $200.00 | $150.00 | $50.00 |
| $250.00 | $187.50 | $62.50 |
| $500.00 | $375.00 | $125.00 |
| $1,000.00 | $750.00 | $250.00 |
Field guide
How to calculate percent off.
Calculating a percentage discount is one of the most practical pieces of everyday math. The formula is short:
Example: A jacket originally priced at $120 is 30% off. Sale price = $120 × (1 − 0.30) = $120 × 0.70 = $84. You save $36.
The savings amount is simply the difference:
Or equivalently, multiply the original price by the discount fraction directly: Savings = $120 × 0.30 = $36.
The calculator above does all of this instantly, just enter the original price and discount %, or use the quick-pick buttons for common discount amounts.
Finding the original price (reverse calculation).
Sometimes you know the sale price and the discount percentage but need to recover the original price. This is the reverse problem, useful when a store shows only the sale price, or when you’re verifying that a stated “% off” is accurate.
Example: You paid $84 for a jacket that was 30% off. What was the original price? $84 ÷ (1 − 0.30) = $84 ÷ 0.70 = $120.
The common mistake is to add the discount % back to the sale price directly. That is wrong. $84 + 30% = $109.20, not $120. The correct approach divides by (1 − discount fraction), because the 30% was applied to the original price, not the sale price.
Switch to Find Original mode in the calculator above, enter the sale price you paid, and the original price appears instantly.
Common percent off values at a glance.
For quick mental arithmetic, a few tricks help:
- 10% off: move the decimal point one place left. $75 → $7.50 off → sale price $67.50.
- 25% off: divide by 4. $80 → $20 off → $60.
- 50% off: divide by 2. $90 → $45.
- 20% off: 2 × the 10% amount. $80 → $8 × 2 = $16 off → $64.
- 15% off: 10% + half of 10%. $80 → $8 + $4 = $12 off → $68.
- 75% off: 50% + 25%. $80 → $40 + $20 = $60 off → $20.
The multi-price reference table in the calculator shows exactly this for your current discount %, across 12 common price points from $5 to $1,000.
Does percent off apply before or after sales tax?
In the United States and most other countries, sales tax is applied to the sale price after the discount, not the original price. This works in the buyer’s favour.
Example: Jacket at $120, 30% off, 8% sales tax.
Tax on the discounted price = $84 × 0.08 = $6.72
Total you pay = $84.00 + $6.72 = $90.72
The total is not $120 × 0.08 = $9.60 tax on the original. You only pay tax on what you actually buy it for. Enter your local tax rate in the optional tax field and the calculator adds it automatically.
The psychology of percent off and when to be skeptical.
A “50% off” tag is one of the most powerful triggers in retail psychology. But before you celebrate, a few questions are worth asking:
- What is the reference price? Is the “original” price a genuine price the item actually sold at, or an inflated MSRP that was never the real market price? Retailers sometimes mark up an item before putting it “on sale.” This is called a fictitious reference pricing strategy, and in some jurisdictions it is illegal.
- Is the % off calculated from the correct base? Always verify: sale price ÷ original price × 100 should equal 100 − discount%. Use the “Find Original” mode to sanity-check.
- Stacked discounts are not additive. A 20% off coupon applied to an item already 20% off does not give you 40% off. It gives you 20% + 20% × 80% = 36% effective discount. The second discount applies to the already-reduced price.
- Per-unit math matters. “Buy 2, get 1 free” is a 33% discount, not 50%. If you only need one item, you get no discount at all.
The “effective” discount on stacked offers
If you apply two percentage discounts in sequence, for example, 30% off during a sale, then an additional 10% off coupon — the effective single discount is:
= 100 − [70 × 90 ÷ 100]
= 100 − 63 = 37% effective discount
Not 40%. The more discounts you stack, the further the combined result falls below the naive sum. For multi-discount calculations, see the Discount Calculator, which has a dedicated stacked-discount field.
Shopping strategy: making percent off work for you.
- Know your break-even quantity. Bulk discounts only pay if you use the item. Extra units stored indefinitely, or worse, wasted, erase the savings.
- Compare absolute savings, not percentages. A 50% off sale on a $10 item ($5 savings) is less valuable than a 10% off sale on a $500 item ($50 savings). The reference table in the calculator makes this vivid — look at the “You save” column, not just the percentage.
- Factor in your tax rate. A $100 item at 20% off in a 10% tax state costs $72 total. The same item at 15% off in a tax-free state costs $85. The higher discount doesn’t always win.
- Use the reverse calculation. If a store advertises “was $X, now $Y,” punch the numbers into Find Original mode to verify the stated discount is correct before deciding it’s a good deal.
Disclaimer
This calculator provides mathematical computations for informational purposes only. Actual prices, taxes, and discounts are determined by retailers and tax jurisdictions. Always verify final prices at checkout.