Discount Calculator
This discount calculator prices your promotions before they go live. Enter the original price and discount percentage for the sale price and per-unit savings, then optionally stack a bulk tier — an extra discount for buying a minimum quantity. You will see the final unit price, the total for the bulk quantity, and the true effective discount, so promos stay profitable.
The regular price before any discount.
The headline sale discount, e.g. 20 for 20% off.
Stack an additional discount for customers who buy the minimum quantity.
Sale price
80
- Discount amountSavings from the headline discount alone.
- 20
- You save per unitVs. original price.
- 20
- Effective discount
- 20%
- Total for 3 unitsAt the sale price (no bulk tier set).
- 240
How it was calculated
- Sale price: $100.00 × 0.80 = $80.00.
- No bulk tier: final unit price stays $80.00.
- Effective discount: $20.00 ÷ $100.00 = 20.0%.
How it works
Sale price = original price × (1 − discount). A 20% discount multiplies the price by 0.80.
Stacked discounts multiply, they do not add: 25% off plus an extra 10% off is 0.75 × 0.90 = 0.675 of the original — a 32.5% effective discount, not 35%.
Effective discount = (original − final unit price) ÷ original × 100, the single percentage that describes the whole promotion.
Bulk totals multiply the final unit price by the minimum quantity, showing exactly what the customer pays.
Worked examples
$100 item at 20% off, no bulk tier
Sale price = 100 × 0.80 = $80. You save $20 per unit — a 20% effective discount. Three units cost $240.
$200 item, 25% off, plus 10% extra on 5+ units
Sale price = $150. Bulk unit price = 150 × 0.90 = $135. Five units = $675, saving $65 per unit — an effective 32.5% off, not 35%, because the discounts multiply.
How to measure
- Start from the price customers actually paid last month, not the aspirational list price.
- Model the discount on your margin first: a 20% discount on a 40% margin wipes out half your profit per unit.
- For bulk tiers, check that the extra discount still beats your per-unit shipping savings at quantity.
- Keep one "regular price" reference — constant discounting trains customers to never pay full price.
- Record the effective discount (not the headline) when comparing promo performance across campaigns.
Assumptions & limitations
Planning estimate
- Stacked discounts are applied multiplicatively (each on the already-discounted price), the standard retail convention.
- Taxes and shipping are excluded; the discount applies to the item price only.
- This is a promotional planning estimate, not financial advice.
Frequently asked questions
Multiply the original price by (1 − discount). For 20% off $100: 100 × 0.80 = $80. The savings are $20. This works for any percentage — just convert it to a decimal first.
No — they multiply. "25% off plus an extra 10% off" is 0.75 × 0.90 = 67.5% of the original price, i.e. 32.5% off, not 35%. Advertising them as additive overstates the deal and understates your margin.
Your gross margin sets the ceiling: with a 40% margin, a 20% discount halves your per-unit profit. Stay above your break-even contribution per unit, and remember that fees are charged on the discounted price, which helps slightly.
Yes — strikethrough pricing ("was $100, now $80") converts better than a bare sale price, and in many jurisdictions the "was" price must have genuinely been offered for a meaningful period. Check local pricing regulations before inventing reference prices.
Often yes: the extra discount is offset by higher units per order, lower per-unit shipping, and fewer transactions to fulfill. Model the bulk unit economics with this calculator and compare total profit per order, not just margin percentage.