Discount / Sale Price Calculator

To find the sale price after a discount, subtract the discount percentage from 100%, then multiply the original price by that fraction. Formula: Sale Price = Original Price * (1 - Discount%/100). For example, a $250 jacket with a 30% discount: $250 * (1 - 0.30) = $250 * 0.70 = $175. Alternatively, calculate the discount amount first ($250 * 0.30 = $75) then subtract from the original ($250 - $75 = $175). In New Zealand retail, advertised prices are GST-inclusive, so the discounted price you calculate is also GST-inclusive — no further GST adjustment is needed at the checkout. Be aware that some stores advertise ex-GST prices (especially trade or wholesale suppliers), in which case you need to add 15% GST to the final sale price. Source: General mathematics and Consumer Guarantees Act 1993 (NZ).

To find the percentage discount when you know the original and sale prices, subtract the sale price from the original, divide by the original, and multiply by 100. Formula: Discount % = ((Original - Sale) / Original) * 100. For example, a TV originally priced at $1,200 now selling for $900: (($1,200 - $900) / $1,200) * 100 = ($300 / $1,200) * 100 = 25%. This is useful in New Zealand for checking whether a store's advertised discount percentage is accurate — under the Fair Trading Act 1986, retailers must not mislead consumers about prices or discounts. If a store says "was $500, now $350" and you calculate the discount as 30% but the sign says 40%, that may be a misleading claim you can report to the Commerce Commission. Source: Commerce Commission NZ (comcom.govt.nz) and Fair Trading Act 1986.

In retail terminology, a discount is a temporary reduction in price as an incentive — such as a weekend sale or promotional code — while a markdown is a permanent reduction in the listed price of a product, typically because it is not selling at its original price or is being discontinued. In New Zealand practice, the terms are often used interchangeably by consumers, but the distinction matters for accounting and inventory management. For GST purposes, both discounts and markdowns reduce the taxable supply amount — a business only accounts for GST on the actual amount received. The Consumer Guarantees Act also affects how businesses handle pricing errors and advertised discounts. For shoppers, the key practical difference is that a markdown may signal that a product is being cleared and is unlikely to revert to its original price. Source: General retail and IRD GST guidance (ird.govt.nz).

In New Zealand, GST applies to the discounted sale price — not the original price. If you offer a 20% discount on a $115 (GST-inclusive) product, the sale price becomes $92 (GST-inclusive), and the GST component is $92 / 1.15 * 0.15 = $12. You account for GST on $92, not on the original $115. For trade discounts between GST-registered businesses, the same principle applies — the GST-registered purchaser can only claim an input tax credit on the discounted amount they actually paid. Loyalty discounts, cash-back offers, and early payment discounts all reduce the GST-inclusive sale price, and GST is calculated on the final amount. Businesses must ensure their GST invoices accurately reflect the discounted amounts. This is governed by the Goods and Services Tax Act 1985. Source: IRD — Discounts and GST (ird.govt.nz/gst).