How to Calculate Percentage Off a Sale Price

Convert the percent to a decimal, multiply by the original price for savings, then subtract from the original for the sale price — or multiply by the complement in one step.

Discount rate (decimal) = percent ÷ 100  (20% → 0.20)

Savings = original × discount rate

Sale price = original × (1 − discount rate)

Also: Sale price = original − savings

Worked example — 30% off

Jacket listed at $120, 30% off.

• Rate = 0.30
• Savings = 120 × 0.30 = $36
• Sale price = 120 × 0.70 = $84

Worked example — 15% off

$45 shirt: savings = 45 × 0.15 = $6.75; sale = $38.25.

Skip the hand math with the free percentage off calculator when you are comparing several tags at once.

Retail uses a short set of percents. Mental shortcuts speed aisle decisions; exact cents still matter online.

Tag	You pay	Shortcut
10% off	90%	Move decimal left on price; subtract
20% off	80%	1/5 off; or 10% × 2
25% off	75%	1/4 off
50% off	50%	Half price
75% off	25%	Quarter of original

$200 item cheat sheet

• 10% off → save $20 → pay $180
• 20% off → save $40 → pay $160
• 40% off → save $80 → pay $120

For arbitrary “what is X% of Y?” steps outside a pure sale context, the percentage calculator is the general-purpose sibling. For a broader retail walkthrough (including reverse original-from-sale), see the discount calculator guide.

Two discounts in a row are not the same as adding the percents. A 20% off sale plus an extra 10% off coupon is not 30% off the original in most checkout systems — the second percent usually applies to the already reduced price.

After first discount: price₁ = original × (1 − r₁)

After second discount: price₂ = price₁ × (1 − r₂)

Combined factor: (1 − r₁) × (1 − r₂)

Worked example

$100 item, 20% off, then 10% off the sale price.

• After 20%: $80
• Then 10% of $80 = $8 → final $72
• Total savings = $28 (28% effective off original)
• Not $30 off (which would be $70)

Effective discount percent = savings ÷ original × 100 = 28%.

When order matters

If one deal is a flat dollar coupon and the other is a percent, store policy decides order (percent first is common). Always read the coupon fine print: “10% off sale price” vs “10% off original” are different promises.

In many U.S. retail flows, tax is calculated on the discounted price, not the pre-sale sticker. Confirm local rules for your category (some goods are exempt or taxed differently).

Taxable base ≈ sale price after all discounts that apply before tax

Tax = taxable base × tax rate

Total due = taxable base + tax

Worked example

$80 item, 25% off, 8% sales tax on the reduced price.

• Sale price = 80 × 0.75 = $60
• Tax = 60 × 0.08 = $4.80
• Total = $64.80

If someone wrongly taxed the $80 first: tax $6.40 + $60 sale = $66.40 — about $1.60 too high vs the usual discount-then-tax order.

For tax-only scenarios or rate lookups in your workflow, pair with the sales tax calculator and the sales tax guide.

Compare final out-the-door totals, not the flashiest percent on a banner. A 40% off item with high shipping can lose to a 25% off item with free shipping.

• Compute sale price for each option
• Add shipping, fees, and tax the same way for both
• Divide total savings by original if you care about effective percent

Restaurant-style tip after discounts

Some people tip on the pre-discount bill; others tip on what they pay. House rules and your preference both appear in the wild. If a check is $50 before a 10% discount ($45 food total) and you tip 20% on the pre-discount amount: tip = $10; on post-discount: tip = $9. Be consistent with how you treat service workers and any automatic gratuity line.

For pure tip math, use the tip calculator or the tip calculator guide.

Enter the original price and discount percent; read savings and sale price. Add a second discount and tax when the tool supports them.

1. Open the free percentage off calculator.
2. Enter the original (sticker) price.
3. Enter the percent off (e.g., 20 for 20% off).
4. Read savings dollars and the sale price.
5. If you have a second coupon, enter the stacked discount on the reduced price.
6. Optionally apply sales tax after discounts for an out-the-door estimate.
7. Compare a second product by changing price and percent only.
8. Note effective percent off when two discounts stacked (savings ÷ original).

Tips for cleaner comparisons

Use the same tax rate when comparing two local store options. Exclude tax when you only want to know which markdown is deeper. Screenshot cart math when flash sales end in minutes.

Bad deal math usually comes from adding percents or taxing the wrong base.

• Adding stacked percents (20% + 10% ≠ 30% off original in sequential coupons)
• Taking “% off” as the amount you pay (30% off means you pay 70%)
• Forgetting tax and shipping when declaring a “final” price
• Comparing a percent off a inflated MSRP to a lower everyday price elsewhere
• Applying tax before discount when the store does the reverse

Deeper retail and general percent help: discount guide, percentage guide, sales tax guide.

This guide is educational consumer math, not tax or retailer policy advice. The register and local rules control what you actually pay.