How to Use This Discount Calculator
Shopping promotions often feature confusing promotional offers like "Take 30% off, plus an extra 15% off at checkout." This tool helps you quickly verify the actual savings:
- Enter Original Price: Input the item's tag or retail list price.
- Enter Main Discount: Type the primary promotional percentage (e.g., 25% off).
- Add Stacked Coupons (Optional): If the store offers an additional clearance or member discount, enter it in the second box. Note that retailers calculate stacked discounts sequentially, not by simply adding percentages together.
- Enter Sales Tax: Include your local municipality's sales tax rate to determine your exact register total.
How Stacked Discounts and Sales Tax are Calculated
Retail stores apply successive discounts sequentially rather than additively. For example, a 20% discount stacked with a 10% coupon does not yield a 30% discount; the second coupon applies only to the already-reduced balance:
2. Stacked Reduced Price = Primary Reduced × [ 1 − (Discount_2 ÷ 100) ]
3. Sales Tax Amount = Stacked Reduced × (Tax Rate ÷ 100)
4. Final Checkout Total = Stacked Reduced + Sales Tax Amount
Step-by-Step Worked Example
Worked Example: $120 Jacket on Sale with Stacked Promo & Tax
- Original Retail Price: $120.00.
- Initial 25% Discount: $120 × 0.25 = $30.00 saved → New price = $90.00.
- Optional 10% VIP Coupon: $90 × 0.10 = $9.00 saved → Price before tax = $81.00.
- Total Direct Savings: $30 + $9 = $39.00 total savings (effective 32.5% discount, not 35%).
- 7% Sales Tax Added: $81.00 × 0.07 = $5.67.
- Final Register Total: $81.00 + $5.67 = $86.67.
Frequently Asked Questions
Why isn't a 20% discount plus a 20% coupon equal to 40% off?
Discounts are applied chronologically. The first 20% discount reduces a $100 item to $80. The second 20% coupon applies to the remaining $80 (saving $16), leaving a final price of $64. That represents a total savings of $36 (or 36% off), not 40% off ($60).
Is sales tax calculated before or after discounts?
In most US states and jurisdictions, retail sales tax is assessed on the final negotiated or discounted sale price that you actually pay to the merchant, rather than the original MSRP sticker price.
How can I calculate what the original price was before a sale?
If you know the sale price and the discount percentage, divide the sale price by $(1 - ext{Discount}/100)$. For instance, if an item is on sale for $60 after a 25% discount, the original price was $60 / 0.75 = $80.
Can this tool handle clearance items with discounts over 90%?
Yes. You can enter any percentage from 0% up to 100% to calculate deep liquidation discounts.