Discount Calculator

Three Discount Calculation Modes

This calculator solves all three discount-related problems. Sale Price: enter original price and discount percentage to find the final price. Original Price: know the sale price and discount but want to find what the item cost originally. % Off: see two prices and want to know the actual discount percentage.

Discount Formulas

Sale Price = Original × (1 − Discount%) Original Price = Sale Price / (1 − Discount%) Discount% = (Original − Sale) / Original × 100

Common Discount Calculations

Original	Discount	You Save	Sale Price
$50	10% off	$5.00	$45.00
$100	25% off	$25.00	$75.00
$200	40% off	$80.00	$120.00
$500	BOGO 50%	$125.00	$375.00

Frequently Asked Questions

For 10% off: move the decimal point left one place ($120 → $12 saved, $108 final). For 25% off: halve the price, halve again, then subtract ($120 → $60 → $30 saved → $90). For 20% off: find 10% and double it ($120 → $12 → $24 saved → $96).

Multiple discounts do NOT add together — they compound. A 20% discount followed by an additional 10% discount is NOT 30% off. First discount: $100 × 0.80 = $80. Second: $80 × 0.90 = $72. Total effective discount: 28%, not 30%. The order does not matter mathematically.

BOGO 50% means the second item is half price — effectively a 25% discount when buying two items. Buy One Get One Free means the second item is $0 — effectively a 50% discount when buying two items. BOGO Free is significantly better. Many retailers display BOGO 50% prominently, knowing it appears similar to BOGO Free.

Divide the sale price by (1 minus the discount as a decimal). For a $75 item at 25% off: Original = $75 / (1 − 0.25) = $75 / 0.75 = $100. This 'reverse percentage' calculation is useful when comparing 'original prices' shown by retailers.