Quick presets
🔄 Reverse: find original price from sale price
How it works
Enter the original price
Type the full price before any discount — in any currency.
Set discount percentage
Enter the % off, or tap a quick preset like 10%, 25%, 50% or 70% off.
Add double discount if applicable
If there is a second discount on top (like 'extra 10% off sale items'), enter it in the second field to see the real combined saving.
Check after-tax total
Enter your GST or sales tax rate to see the actual out-of-pocket price after both discount and tax are applied.
Discount calculation formula in code
Need to calculate discounts programmatically for a cart or invoice system?
How to calculate a discount — the formula explained simply
Multiply the original price by (1 minus the discount rate as a decimal): a 20% discount on Rs 5,000 = 5,000 × 0.80 = Rs 4,000. You save Rs 1,000. This calculator does this math instantly for any price and any percentage, plus handles the two complications that trip most shoppers: double discounts and sales tax.
The core formula is deceptively simple, but real-world shopping introduces layers of complexity that mental math struggles with. When a store advertises “30% off + extra 20% off”, most shoppers instinctively assume they are getting 50% off — but the actual effective discount is only 44%. When GST or sales tax is added after the discount, the “saving” shrinks further in a way that is genuinely hard to feel intuitively at the checkout counter. This calculator makes all of those hidden numbers visible before you commit to a purchase.
The double discount trap — why 30% + 20% off is NOT 50% off
This is the single most important thing this calculator reveals, and it is the reason the double discount field exists. When a store applies two successive discounts, the second percentage applies to the already-reduced price, not the original price. Here is how it works with actual numbers:
Original price: Rs 10,000. First discount 30%: Rs 10,000 × 0.70 = Rs 7,000. Second discount 20%: Rs 7,000 × 0.80 = Rs 5,600. Your total saving is Rs 4,400 out of Rs 10,000 — that is 44% effective discount, not 50%. The store's marketing says “30% + 20% off” which sounds like half price, but you are actually paying 56% of the original price. This 6-percentage-point gap grows larger with bigger discounts and represents real money on expensive purchases like electronics, furniture or clothing.
When tax changes your deal more than you expect
In Pakistan, GST at 18% is typically charged after the discount is applied. This means your “saving” is calculated before tax, but your actual payment includes tax on the discounted price. Example: Rs 5,000 item at 20% off becomes Rs 4,000, but with 18% GST the final out-of-pocket price is Rs 4,720. Your real saving compared to the shelf price with tax (Rs 5,900) is Rs 1,180 — not the Rs 1,000 the “20% off” banner implied. The Tax/GST field makes this final number visible so you know your actual budget impact before reaching the counter.
Using this calculator for comparison shopping
When two stores offer different discount structures on the same item — one at a straight 30% off, another at 20% off plus an extra 15% off for card holders — enter both scenarios and compare the effective discount percentages directly. The effective discount normalizes any combination of single, double or promotional discounts into a single comparable number, making the better deal immediately obvious even when the marketing is deliberately structured to make comparison difficult. Stores know that “20% + 15% off” sounds bigger than “30% off” even though 30% is actually the better deal (30% vs 32% effective).
Reverse calculator — finding the original price from a sale price
Sometimes you see an item with a price tag that says “after 25% discount” but does not show the original price. The reverse calculator at the bottom of this tool solves this: enter the sale price and the discount percentage, and it calculates what the original price was. The formula is simple: original = sale price ÷ (1 − discount/100). For example, if you paid Rs 3,750 after a 25% discount, the original was Rs 3,750 ÷ 0.75 = Rs 5,000. This is also useful for verifying that a store's “original” price claim is consistent with the discount they are advertising.
| Discount level | Typical scenario | Watch out for |
|---|---|---|
| 10% off | Token / new customer discount | Often not better than a competitor's regular price |
| 20-25% off | Seasonal sale, Eid/holiday promotions | Check if tax is included or added separately |
| 50% off | End-of-season clearance | Limited sizes, colors or stock available |
| 70%+ off | Liquidation, loss-leader pricing | Double-discount tricks inflating the headline number |
What common discount levels signal about the deal — and what to verify
💡 Key takeaways
- Free discount calculator with instant sale price, savings amount and effective discount percentage
- Double discount support reveals the true combined saving — 30% + 20% off is only 44%, not 50%
- Tax / GST field shows the real out-of-pocket price after both discount and government tax
- Quick presets: 10%, 20%, 25%, 50%, 70% off — one tap for the most common sale percentages
Pro tip: When a store advertises “30% off + extra 20% off,” enter 30 as the first discount and 20 as the double discount — the effective rate (44%, not 50%) shows what you are actually saving. This one check can change your buying decision on expensive items.
Why choose our tool?
100% Private
Everything runs in your browser. No uploads, no tracking, no server processing.
Instant Results
Results update as you type — no submit button needed, no waiting.
No Sign-Up Ever
No accounts, no emails. Open and use — forever free.
Works Everywhere
Phone, tablet, desktop — any browser, any OS, works offline.
Also useful if you searched for: discount calculator, percentage off calculator, sale price calculator, how to calculate discount, double discount calculator, price after discount, 20 percent off calculator, discount percentage formula, GST discount calculator, original price from sale price.