How to Calculate Discount and Sale Price (Percent Off, Examples)

Store tags say “30% off” or “Was $120, now $84.” To know what you are really paying—and whether a deal is as good as it sounds—you need two basic skills: find the sale price from a percent off, and find the discount percent when only two prices are shown. This guide covers both, with worked examples, and links to our free discount calculator for instant answers.

The core idea

A discount is a percentage taken off the original (regular) price.

• Amount saved = original × (discount ÷ 100)
• Sale price = original − amount saved

You can also write sale price in one step:

Sale price = original × (1 − discount ÷ 100)

Example: 25% off $80 → save $20 → pay $60.

Method 1: You know the percent off

Example: 30% off a $120 jacket

1. Savings: 120 × (30 ÷ 100) = 120 × 0.30 = $36
2. Sale price: 120 − 36 = $84

Or: 120 × (1 − 0.30) = 120 × 0.70 = $84

Example: 10% member discount on $45

• Save: 45 × 0.10 = $4.50
• Pay: $40.50

Small percents use the same formula—no shortcut needed beyond moving the decimal (10% = one-tenth).

Example: Half price (50% off) on $64

• Save: $32
• Pay: $32 (half of original)

Method 2: You know original and sale price (find the % off)

Black Friday tags often show was / now without stating the percent.

Discount % = ((original − sale price) ÷ original) × 100

Example: Was $249, now $179

1. Amount saved: 249 − 179 = $70
2. Percent off: (70 ÷ 249) × 100 ≈ 28.1%

So it is not “30% off” unless the store rounds up in marketing copy—always verify with the formula.

Example: Shelf $80, clearance $60

• Saved: $20
• (20 ÷ 80) × 100 = 25% off

Our discount calculator has a “Find discount %” mode for this case.

Quick mental math: the 10% trick

10% of a price = move the decimal one place left.

• 10% of $85 = $8.50
• 20% off = double that → save $17
• 30% off = triple 10% → save $25.50 on $85

For messy numbers or cents, use the calculator.

Stacked discounts (20% + extra 10%)

Stores sometimes advertise two discounts. They usually do not add to 30% straight.

Typical pattern: apply the first discount, then apply the second percent to the new price.

Example: $100 with 20% off, then extra 10% off the reduced price:

1. After 20%: $80
2. 10% off $80: save $8 → $72 final

That is equivalent to 28% off $100, not 30%. Run each step separately or read the fine print.

Tax and coupons

• Most retailers discount the pretax price, then add sales tax on what you pay.
• A coupon that is “20% off” is usually the same math as a shelf discount.
• $10 off fixed coupons are different: subtract $10 from original (if allowed), then tax rules apply.

This guide and calculator focus on percent-off and sale price math, not tax.

Common mistakes

1. Dividing by the sale price instead of the original when finding % off — always divide savings by original.
2. Thinking 50% off twice = 100% off — second percent applies to a smaller number.
3. Rounding too early — keep extra digits until the last step on money problems.
4. Comparing “$50 off” vs “50% off” on different base prices — percent depends on original amount.

Percent off vs “percent of”

Discount math is a subset of percentage math focused on prices.

Practice problems (with answers)

1. 40% off $90 → save $36, pay $54
2. 15% off $200 → save $30, pay $170
3. Original $55, sale $44 → save $11 → (11÷55)×100 = 20% off
4. 35% off $140 → save $49, pay $91
5. Was $99, now $74.25 → save $24.75 → 25% off

When to use the discount calculator

Open the free discount calculator when you want:

• Percent off → sale price and amount saved
• Two prices → exact discount percent
• Results as you type on a phone in-store

For tips, tax estimates, or test scores, use the percentage calculator. For restaurant bills, see how to calculate a restaurant tip.

---

Bottom line: Amount saved = original × discount ÷ 100; sale price = original minus savings. To find % off from two prices, divide savings by the original and multiply by 100. For fast checks in the aisle, use the free discount calculator.