What it really costs after the discount — including stacked offers and the true combined percentage.
A discount reduces a price by a percentage of itself: final = price × (1 − discount/100). 20% off 200 leaves 160, saving 40. Simple — until offers stack.
“20% off, plus an extra 10% off at checkout” is not 30% off. The second discount applies to the already-reduced price: 200 × 0.80 × 0.90 = 144, an effective discount of 28%. Retailers rely on shoppers reading 30; the gap widens with bigger numbers (50% + 50% is 75% off, not free). This calculator shows the true effective rate for any pair of stacked discounts.
The invoice generator supports both per-line discounts (a % column on each item) and a document-level discount (percent or fixed) shown as its own row before tax — so the client sees exactly what was given, and the tax computes on the discounted base, as it should.
Multiply the price by 0.80 — or by (1 − rate/100) for any rate. 20% off 250 is 200.
No — stacked discounts multiply. 20% then 10% is a 28% effective discount, because the 10% applies to the already-reduced price.
After — tax applies to what the customer actually pays. Our invoice generator applies document discounts before computing tax for exactly this reason.
Depends on your margin: discount ÷ margin is the share of profit you give up. At a 30% margin, a 15% discount costs half your profit on the sale.