Discounts are everywhere — from Black Friday sales to wholesale pricing to subscription renewals. Knowing how to calculate a discount quickly means you’ll never overpay, and you’ll always know if a deal is actually a deal. This guide covers every discount scenario you’ll encounter.
How to Calculate Discount Amount
Discount Amount = Original Price × Discount Rate ÷ 100
Example: A $80 item is 25% off.
Discount = $80 × 25 ÷ 100 = $20 off
How to Calculate the Final Price After Discount
Final Price = Original Price × (1 − Discount Rate ÷ 100)
Example: $80 item with 25% off.
Final Price = $80 × (1 − 0.25) = $80 × 0.75 = $60
How to Find the Discount Percentage
If you know the original and sale price but want to find the discount percentage:
Discount % = (Original − Sale Price) ÷ Original × 100
Example: Was $120, now $84.
Discount % = (120 − 84) ÷ 120 × 100 = 36 ÷ 120 × 100 = 30% off
Discount Quick Reference Table
| Original Price | 10% Off | 20% Off | 30% Off | 50% Off |
|---|---|---|---|---|
| $20 | $18 | $16 | $14 | $10 |
| $50 | $45 | $40 | $35 | $25 |
| $100 | $90 | $80 | $70 | $50 |
| $250 | $225 | $200 | $175 | $125 |
| $500 | $450 | $400 | $350 | $250 |
Stacked Discounts: How to Calculate Multiple Discounts
When two discounts are applied in sequence, you cannot simply add them. A 20% discount followed by a 10% discount is NOT a 30% discount.
Example: $100 item, 20% off then 10% off.
After 20% off: $100 × 0.80 = $80
After 10% off: $80 × 0.90 = $72 (not $70)
The combined effective discount = 1 − (0.80 × 0.90) = 1 − 0.72 = 28% total, not 30%.
Discount vs. Sale vs. Markdown: What’s the Difference?
- Discount — a reduction from the regular price, often percentage-based
- Sale price — the reduced price after a discount is applied
- Markdown — a permanent price reduction (often at retail when clearing inventory)
- Coupon — a code or voucher that applies a specific discount, often with restrictions
How to Know if a Sale Is Actually a Good Deal
Retailers sometimes inflate the “original price” before a sale. Always check the price history of a product before buying. A “50% off” claim means nothing if the original price was artificially inflated. Tools like browser extensions that track price history can help you spot fake markdowns.
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