Discount Calculator
Work out the sale price and how much you save on any discount, with optional stacked deals and sales tax.
About the Discount Calculator
The Discount Calculator turns a "percent off" into real numbers in seconds: exactly how much you save and what you'll actually pay at the register. Type in the original price, pick a discount with a quick preset or enter your own, and the tool instantly shows the amount saved and the final sale price. It's built for those everyday moments — a clearance rack, a flash sale, a coupon code — when you want to know the true cost before you commit rather than trusting the sticker.
Retail discounts sound simple but trip a lot of people up, especially once a store advertises "an extra 20% off already-reduced prices" or the total needs sales tax added at checkout. This calculator handles both. You can stack a second discount on top of the first (applied to the already-marked-down price, the way most "extra off" promotions actually work) and add a sales-tax percentage so the final figure matches what the cashier will ring up. Everything runs directly in your browser, so it's fast, private, and works even if your signal drops in the middle of a store.
How to use
- Enter the original price in the "Original price" box — the full pre-discount amount on the tag.
- Choose a discount percentage by tapping one of the quick presets (10%, 20%, 25%, 30%, or 50%), or type any custom percentage into the field below the presets.
- Add a second discount (optional) if the deal stacks — for example an extra percentage off the sale price. It's applied to the already-discounted amount, not the original.
- Add sales tax (optional) by entering your local tax rate. The tax is calculated on the discounted price and added to the total.
- Read the results. The panel shows how much you save, the price after discount, any tax added, and the final price you'll pay.
Every value updates the moment you change an input, so you can try different discount levels and instantly see how they change the bottom line. If a field is empty or invalid, the tool simply shows a dash instead of a confusing error, so you're never staring at "NaN."
Frequently asked questions
How is the sale price calculated?
The tool multiplies your original price by the discount to find the amount off, then subtracts it. For example, $80 at 25% off is a saving of $80 × 0.25 = $20, giving a sale price of $60.00. Displayed amounts are rounded to two decimal places, formatted as currency.
How does the second (stacked) discount work?
The second discount is applied to the price after the first discount, not to the original price — which is how most "take an extra X% off sale items" promotions really work. So $80 with 25% off becomes $60, and an extra 10% off that gives $54.00, not the $52 you'd get from naively adding 25% + 10% = 35%. This distinction can save you from over- or under-estimating a stacked deal.
Does it include sales tax?
Only if you want it to. Leave the sales-tax field blank and the calculator just shows the discounted price. Enter your local rate and it calculates tax on the discounted amount and adds it to the final total, so the number matches what you'll actually pay at checkout. Tax rates vary by location, so use whatever figure applies where you're shopping.
What if I enter a discount over 100%?
Discount percentages are capped at 100%, since you can't be more than fully discounted. If you type a larger number the tool treats it as 100% (a free item, before any tax). Negative discounts are treated as zero. This keeps the results sensible no matter what you enter.
Why do I sometimes see a dash instead of a number?
A dash ("—") appears whenever the tool doesn't have enough valid information to calculate — for instance if the original price or discount is blank or not a number. It's a deliberate, friendly placeholder that prevents confusing "NaN" errors. Fill in a valid original price and discount and the results appear right away.
Is my data sent anywhere?
No. The Discount Calculator runs entirely in your browser — nothing you type is uploaded, saved, or shared. All the math happens locally on your device, which also means it keeps working offline once the page has loaded, handy when you're shopping somewhere with a weak connection.