Percentage Off Calculator: Free Discount & Savings Tool
How much is that really off? This percentage off calculator solves discounts three ways: enter the price and discount to get the sale price, enter both prices to find the discount percentage, or enter the sale price and discount to work the original price back out. Add a stackable coupon, include sales tax, and get a full breakdown you can copy or share.
The three percentage-off formulas
Every discount question is one of three calculations. Pick the mode in the calculator that matches what you know:
- Sale price = Original price x (1 - discount / 100). You know the price and the percent off.
- Discount % = (Original price - Sale price) / Original price x 100. You know both prices and want the percent.
- Original price = Sale price / (1 - discount / 100). You know what you paid and the percent off, and want the pre-sale price.
Worked example: 25% off $120
- Sale price: $120 x (1 - 25/100) = $120 x 0.75 = $90.00.
- You save: $120 - $90 = $30.00.
- Reverse check: ($120 - $90) / $120 x 100 = 25%.
- Work the original back out: $90 / 0.75 = $120.00.
Add a stacked 10% coupon and 8% sales tax: $90 x 0.90 = $81.00 after both discounts, and $81.00 x 1.08 = $87.48 at checkout. The combined discount is 32.5%, not 35%.
The pay-multiplier shortcut
Instead of computing the savings and subtracting, multiply the price by what you actually pay: 25% off means you pay 75%, so multiply by 0.75. Common multipliers: 10% off = 0.90, 20% off = 0.80, 25% off = 0.75, 30% off = 0.70, 50% off = 0.50. This is the fastest way to sanity-check a sale price in your head.
Stacked discounts multiply, they never add
"25% off plus an extra 10% off" is not 35% off. The second discount applies to the already-reduced price: $120 becomes $90, and 10% off $90 is $9, landing at $81. The true combined discount is 32.5%. Any calculator that adds stacked discounts is wrong; this one multiplies them, and shows the combined percent so you can see it.
Honest limitations
The calculator trusts the numbers you enter; it cannot know about excluded items, minimum purchase thresholds, or coupons that cannot be combined. Tax is applied to the discounted price, which is how most states compute it, but rules vary. A discount above 100% is impossible in the real world, so the tool refuses it rather than showing a negative price.
Frequently asked questions
How do I calculate percentage off a price?
Multiply the original price by (1 - discount / 100). For 20% off $80: $80 x 0.80 = $64. The amount saved is the original minus the sale price: $16.
How do I find the discount percentage from two prices?
Subtract the sale price from the original, divide by the original, and multiply by 100. For $120 down to $90: ($120 - $90) / $120 x 100 = 25%.
How do I find the original price from a sale price?
Divide the sale price by (1 - discount / 100). For a $90 item at 25% off: $90 / 0.75 = $120.
Are stacked discounts the same as their sum?
No. 25% then 10% is not 35% off. The second discount applies to the reduced price: $120 to $90 to $81, which is 32.5% off the original.
What is 30% off $150?
You save $45 and pay $105.
What is the difference between percent off and dollars off?
A "$20 off" coupon subtracts a fixed $20 no matter the price. A "20% off" sale subtracts a fifth of the price, so the dollar savings grow with more expensive items: $10 off a $50 item but $40 off a $200 item.
Is sales tax calculated before or after the discount?
After, in most states. The discount comes off first, then tax applies to the lower price, which also saves you a little on tax.
Can a discount be more than 100%?
No. 100% off means free; anything above that would mean the store pays you, which is not a discount. The calculator rejects values over 100%.