Discount Calculator

What It Does

This calculator solves all three discount problems in one place: find the final sale price given an original price and discount percent, find the original price given a sale price and discount, or find the discount percentage given both prices. Optional tax calculation applies the tax rate after the discount is applied.

Discount Formulas

• Final price: original × (1 - discount%/100)
• Savings amount: original × (discount%/100)
• Original price: sale price ÷ (1 - discount%/100)
• Discount percent: ((original - sale) ÷ original) × 100
• Final price with tax: sale price × (1 + tax%/100)

Example Calculations

• $120 jacket at 30% off → $120 × 0.70 = $84 (saving $36)
• Item priced $45 was originally $60 → discount = (15 ÷ 60) × 100 = 25% off
• $84 sale price + 8.5% tax → $84 × 1.085 = $91.14 total

Stacked Discounts

When multiple discounts apply (e.g., 20% off + an extra 10% off), they are applied sequentially, not added together. A 20% discount followed by 10% off is not 30% off — it is effectively a 28% reduction: $100 × 0.80 × 0.90 = $72, not $70.

Frequently Asked Questions

How do I calculate the final price after a percentage discount?

Multiply the original price by (1 minus the discount rate). For example, a 25% discount on a $80 item: $80 × (1 - 0.25) = $80 × 0.75 = $60. Alternatively, calculate the discount amount ($80 × 0.25 = $20) and subtract it from the original price.

How do I find the original price if I only know the sale price and discount percent?

Divide the sale price by (1 minus the discount rate). For example, if an item is $60 after a 25% discount: $60 ÷ (1 - 0.25) = $60 ÷ 0.75 = $80 original price.

How do I calculate what percentage discount I received?

Subtract the sale price from the original price to get the savings, then divide by the original price and multiply by 100. Example: original $80, sale $60 → savings = $20 → discount % = (20 ÷ 80) × 100 = 25%.

How does tax interact with a discount?

Tax is typically applied after the discount. Calculate the discounted price first, then apply the tax rate to that amount. Example: $80 item with 25% off and 10% tax → $60 discounted price → $60 × 1.10 = $66 final price. Some jurisdictions apply tax before certain discounts — check local rules for retail compliance.

What is the difference between a percentage discount and a fixed amount discount?

A percentage discount (e.g., 20% off) scales with the price — a larger discount on more expensive items. A fixed amount discount (e.g., $10 off) is the same regardless of the original price. Percentage discounts are more common in retail; fixed discounts are typical for coupon codes and promotional credits.