Percent Off Calculator · Practical guide
How to Calculate 20 Percent Off a Price
Twenty percent off means you pay 80% of the list price — here is the fast math, a lookup table, and mental shortcuts.
At a glance
The 20 Percent Off Formula
To calculate 20 percent off a price, multiply the original price by 0.8. That is the whole trick: 20% off means you still pay 80% of the price, and 80% as a decimal is 0.8. A $50 item at 20% off costs $50 × 0.8 = $40, and you save $10. A $79.99 item costs $79.99 × 0.8 = $63.992, which displays as $63.99 — a saving of $16.00.
Formally: Sale price = Original price × (1 − 20 ÷ 100), and the amount saved is Original price × 0.2.
Interactive tool
Percent Off Calculator
Enter your own values, then compare the result with the examples below.
Discount Breakdown
20% Off Lookup Table
| Original Price | You Save | You Pay |
|---|---|---|
| $25.00 | $5.00 | $20.00 |
| $50.00 | $10.00 | $40.00 |
| $75.00 | $15.00 | $60.00 |
| $100.00 | $20.00 | $80.00 |
| $150.00 | $30.00 | $120.00 |
| $200.00 | $40.00 | $160.00 |
Do It in Your Head
Find 10% by moving the decimal one place left, then double it. For a $64.99 item, 10% is about $6.50, so 20% is about $13 off, and you pay roughly $52. The exact figure is $51.99 — close enough to decide whether the deal is worth it while you are standing in the aisle.
Watch for Stacked Discounts and Tax
If the store takes an extra 10% off the reduced price, the total is not 30% off: $100 falls to $80, then to $72 — an effective 28% discount. Sales tax comes last, calculated on the discounted price, so 8% tax on that $72 adds $5.76 for an out-the-door total of $77.76.
Frequently Asked Questions
Is 20% off the same as paying 80%?
Yes, exactly. Taking 20% off leaves 80% to pay, which is why multiplying the price by 0.8 gives the sale price in one step.
How much is 20 percent off $100?
You save $20 and pay $80. For any round price, just take 20% as one-fifth of the price.
What is 20 percent off $39.99?
$39.99 × 0.8 = $31.992, displayed as $31.99. You save $8.00.
Is 20% off better than a $10 coupon?
It depends on the price. Twenty percent off beats $10 off once the item costs more than $50; below $50, the flat $10 coupon saves more.