Do discounts of 20% and 10% add up to 30%?

Successive discounts apply to different prices. A simple example helps you check a promotion correctly.

The price falls at each step

Imagine an item costing €100. A 20% discount removes €20: the price becomes €80. The second discount of 10% applies to those €80, removing another €8. You finally pay €72. The total saving is €28, an overall discount of 28%. Simply adding 20 and 10 therefore overstates the benefit of the offer.

Use multiplying factors

Keeping 80% of a price means multiplying it by 0.80. Then keeping 90% means multiplying the result by 0.90. The overall factor is 0.80 × 0.90 = 0.72. You retain 72% of the starting price and save the remaining 28%. This method works for any starting price and for more than two discounts, provided they can actually be combined.

Compare two offers on the same basis

A single 30% discount on €100 gives €70. It is therefore better than the two previous discounts by €2. But a higher percentage does not always mean the best purchase if starting prices differ. Compare the final price, delivery costs, quantities and product features. A displayed discount alone does not establish an offer's value.

Check conditions and rounding

Read how the discounts are applied: some exclude already reduced items or require a minimum purchase. The calculator assumes both discounts are successive and permitted. It retains precision during calculation; a till may round amounts at each step. For small sums, a one-cent difference may result from that convention. Keep the starting price and both rates so you can repeat the calculation.

Put it into practice

• Price after discount
• Successive discounts
• Value before an increase

Educational text prepared with AI assistance. The examples use adjustable assumptions and are not personal advice.