Discount Calculator
Calculate sale prices, percentage off, and total savings. Supports multiple discounts and optional tax calculations for accurate shopping totals.
Total Savings
$0.00
(0.0% off)
Quick Answer: Discount Formula
To calculate a discount: Sale Price = Original Price × (1 - Discount%/100)
Dr. Snezana Lawrence
Mathematical Historian
15+ years experience
PhD from Yale University. Published mathematical historian ensuring precision in all calculations.
Education
PhD in Mathematical History - Yale University
Table of Contents
How to Use This Discount Calculator
Our discount calculator makes it easy to figure out sale prices and total savings. Follow these simple steps:
- Enter the original price - Type in the regular price before any discounts
- Enter the discount percentage - Type a number or use the quick-select buttons
- Add a second discount (optional) - For stacked deals like "20% off + extra 10%"
- Include sales tax (optional) - Enter your local tax rate for the final total
- View your savings - See the discounted price, total savings, and effective discount percentage
Pro Tip: When comparing deals, always look at the effective discount percentage. Two 15% discounts don't equal 30% off - our calculator shows you the true savings!
Quick Discount Reference Table
Common discount calculations for various price points:
| Price | 10% Off | 20% Off | 25% Off | 50% Off | 75% Off |
|---|---|---|---|---|---|
| $25 | $22.50 | $20.00 | $18.75 | $12.50 | $6.25 |
| $50 | $45.00 | $40.00 | $37.50 | $25.00 | $12.50 |
| $75 | $67.50 | $60.00 | $56.25 | $37.50 | $18.75 |
| $100 | $90.00 | $80.00 | $75.00 | $50.00 | $25.00 |
| $150 | $135.00 | $120.00 | $112.50 | $75.00 | $37.50 |
| $200 | $180.00 | $160.00 | $150.00 | $100.00 | $50.00 |
| $500 | $450.00 | $400.00 | $375.00 | $250.00 | $125.00 |
| $1000 | $900.00 | $800.00 | $750.00 | $500.00 | $250.00 |
How to Calculate Discounts
Single Discount Formula
The easiest way to calculate a discount is using this formula:
Example: $100 × (1 - 20/100) = $100 × 0.80 = $80
Alternative Method
You can also calculate the discount amount first:
Sale Price = Original Price - Discount Amount
Example: $100 × 0.20 = $20 discount, Sale Price = $100 - $20 = $80
Finding the Discount Percentage
If you know the original and sale prices, find the discount percentage:
Example: (($100 - $75) / $100) × 100 = 25% off
Understanding Stacked Discounts
When stores offer multiple discounts like "20% off + extra 10% off," many shoppers assume they're getting 30% off. However, stacked discounts work differently and the second discount applies to the already-reduced price.
Important: 20% + 10% ≠ 30%
The second discount is applied to the reduced price, not the original price. This means you're actually saving less than you might think!
Example: $100 item with "20% off + extra 10% off"
Step 1: $100 × 0.80 = $80 (after 20% off)
Step 2: $80 × 0.90 = $72 (after extra 10% off)
Total savings: $28 (28% effective discount, not 30%!)
Stacked Discount Reference
| First Discount | + 10% | + 15% | + 20% |
|---|---|---|---|
| 10% off | 19% | 23.5% | 28% |
| 20% off | 28% | 32% | 36% |
| 30% off | 37% | 40.5% | 44% |
Smart Shopping Tips
Percent Off vs. Dollar Off
When choosing between "25% off" and "$25 off," remember:
- • Under $100: $25 off is better
- • At $100: They're equal
- • Over $100: 25% off is better
Tax Savings Bonus
Sales tax is calculated on the discounted price, not the original. A $100 item at 20% off with 10% tax costs $88, not $90!
Clearance Math
An item "marked down from $100 to $60" is actually 40% off, even if not advertised that way. Always calculate the actual discount.
Price Per Unit
When comparing different sizes on sale, calculate the price per unit (oz, lb, etc.) to find the truly better deal.
Frequently Asked Questions
How do I calculate a discount percentage?
To calculate a discount: Multiply the original price by the discount percentage, then divide by 100. Subtract this amount from the original price to get the sale price. For example, 20% off $50: $50 × 20 ÷ 100 = $10 savings, sale price = $40.
How do multiple discounts work?
Multiple discounts are applied sequentially, not added together. A 20% off plus an additional 10% off does NOT equal 30% off. The second discount applies to the already-reduced price. Example: $100 with 20% off = $80, then 10% off $80 = $72 (not $70).
What is the formula for calculating sale price?
Sale Price = Original Price × (1 - Discount Rate). For example, with a 25% discount: Sale Price = Original Price × 0.75. You can also calculate: Sale Price = Original Price - (Original Price × Discount ÷ 100).
Is it better to get 25% off or $25 off?
It depends on the original price. For items under $100, $25 off is better than 25% off. For items over $100, 25% off saves more. At exactly $100, they're equal. Always calculate both to see which gives you more savings.
Should tax be calculated before or after the discount?
Sales tax is calculated on the final discounted price, not the original price. This means you save money on both the item price AND the tax amount when using a discount.
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Dr. Snezana Lawrence
Mathematical Historian | PhD from Yale
Dr. Lawrence is a published mathematical historian with a PhD from Yale University. She ensures mathematical precision and accuracy in all our calculations, conversions, and academic score calculators. Her expertise spans computational mathematics and educational assessment.
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