Successive Discounts Explained: Why 20% + 10% Is Not 30%

In a sale you often see offers like "20% off plus extra 10% off". Many people add them and think the total is 30%, but that is not how it works. The second discount is taken on the already reduced price, so the real discount is a little less. Here is how to calculate it correctly.

Formula: Final price = Original price x (1 - d1/100) x (1 - d2/100). Total discount % = 100 - (final price / original price x 100).

Example: 20% and 10% on Rs 2,000

Step 1: First discount

20% of Rs 2,000 is Rs 400, so the price becomes Rs 1,600.

Step 2: Second discount

10% of Rs 1,600 is Rs 160, so the price becomes Rs 1,440.

Step 3: Total discount

Total saving is Rs 560, which is 28% of Rs 2,000, not 30%.

If it were a single 30% discount, you would pay Rs 1,400. So 20% plus 10% successive is slightly worse than a flat 30%.

More Examples

Offers	Real total discount	Price of Rs 1,000 item
10% then 10%	19%	Rs 810
20% then 10%	28%	Rs 720
30% then 20%	44%	Rs 560
50% then 20%	60%	Rs 400
50% then 50%	75%	Rs 250

Flat Amount Off vs Percentage Off

To compare a flat amount with a percentage, convert both to the final price. For a Rs 3,000 item, "Rs 500 off" gives Rs 2,500. "15% off" gives Rs 2,550. So here the flat discount is better. On a Rs 6,000 item, 15% gives Rs 5,100, while Rs 500 off gives Rs 5,500, so the percentage is better.

Where GST Fits

GST is generally charged on the price after discount, when the discount is shown on the invoice. Check your bill, and use the GST Calculator to add or remove GST from a price.

Calculate your discount

Enter price and discount to see the saving and final price.

Discount Calculator Percentage Calculator

Tips While Shopping

Always compare the final price you pay, not the percentage on the tag.
Check delivery, packaging and convenience fees.
Compare the price on two or three sites before buying.
Be careful with offers that raise the price first and then show a discount.

Frequently Asked Questions

No. The second discount applies to the reduced price, so 20% then 10% equals a total of 28%.

Final price = original price x (1 - d1/100) x (1 - d2/100).

Compare the final price. It depends on the item price and the discount values.

Generally on the discounted price when the discount is shown on the invoice. Check your bill.