Math Playground
Back to Money

Money › Discounts

Percentages & discounts

When the sign says 25% off, what does it actually cost? This is where percentages stop being abstract.

Discount calculator

See exactly how much "X% off" actually saves you.

Discount25%

Discount: $20.00 = (25/100) × $80.00

You pay: $80.00 − $20.00 = $60.00

You pay

$60.00

Saved $20.00

Two ways to compute it

  1. Find the discount: price × (percent / 100). Then subtract.
  2. Or, multiply by the amount you keep: price × ((100 − percent) / 100). One step.

Mental math shortcuts

  • 10% off — divide by 10, subtract.
  • 20% off — divide by 5, subtract. Or take 10% twice.
  • 50% off — half.
  • 25% off — quarter off. The price you pay is three-quarters.

Tax, the other direction

Sales tax goes the other way: 8% tax on $50 means you pay $50 × 1.08 = $54. Multiplying by 1.08 is faster than finding 8% and adding it.

Stacked discounts

A coat is 20% off, and you have a coupon for an extra 10% off the sale price. That's not 30% off. After the first discount you pay 80%; after the second, 90% of that. Total: 0.8 × 0.9 = 0.72, or 28% off the original.