How to calculate discounts and percentages, including successive reductions

Identify the amount that the percentage applies to

A percentage describes a share of a base amount. Twenty percent of an $80 price is $16 because 80 × 20 ÷ 100 = 16. Subtracting that amount leaves a sale price of $64. The base is the original price, not the discount amount or the final price.

For a discount rate r and original price P, savings = P × r ÷ 100 and sale price = P × (1 − r ÷ 100). A discount between 0% and 100% is accepted by the tool. A 100% discount leaves zero; a negative price or a rate above 100% is not a valid ordinary sale-price input.

Use the discount tool and inspect both outputs

1. Open Discount Calculator. Enter the original price using the currency amount from the offer.
2. Enter the discount rate as 20 for 20%, rather than 0.20. Select Calculate.
3. Read both the discount amount and the sale price. Check whether shipping, taxes and other charges are included in the advertised price.
4. For a second reduction applied to the sale price, use the first result as the next original price. Keep the stages separate so the base amount is clear.

Example: two reductions do not simply add

An $80 item discounted by 20% first costs $64. A further 10% reduction on $64 saves $6.40 and leaves $57.60. Total savings are $22.40, or 28% of the original $80. Adding 20% and 10% would incorrectly predict a 30% reduction and a $56 price.

The combined factor is 0.80 × 0.90 = 0.72, so the combined reduction is 1 − 0.72 = 0.28. This example assumes the second discount applies to the first discounted price. A voucher with a spending threshold, maximum saving or excluded items may follow different rules.

Use the percentage calculator for other questions

To find what percentage 18 orders represent out of 60 orders, use share mode: 18 ÷ 60 × 100 = 30%. To compare a price changing from $50 to $60, use change mode: (60 − 50) ÷ 50 × 100 = a 20% increase. The whole or starting amount must not be zero.

An increase and a decrease of the same percentage do not cancel. Increasing $100 by 10% gives $110; decreasing that by 10% gives $99 because the second base is larger. State the starting and ending amounts when reporting a percentage change.

Rounding and offer conditions

The tools display monetary estimates to two decimal places. Retailers may round per item or per order, and the currency or cash payment method may use different rounding rules. Keep the unrounded factors through the calculation and compare the provider’s final payable amount.

Discounts do not automatically include taxes, delivery, minimum spend or eligibility rules. Read the offer terms and use the VAT calculator separately if you need to add or extract a specified tax rate. No tax jurisdiction or merchant policy is inferred by this calculation.