Buy two, get one free or 30% off: which offer costs less?
Convert promotions into a unit price for identical goods, then consider whether you need the required quantity. The lowest unit price is not always the lowest useful purchase cost.
Discount calculator →Compare like-for-like quantities
Items should have the same size and relevant specification before their unit prices are compared. A multi-buy promotion spreads the saving over a group, while a percentage discount reduces each eligible price directly. A different free item should not automatically be valued at its advertised price if it does not replace something you would otherwise buy.
Calculate a three-item example
At a regular price of 30 each, buying two and receiving a third free costs 60 for three items. Unit price is 20, equivalent to approximately 33.33% off. With 30% off each item instead, each costs 21 and three cost 63. If you need exactly three identical items, the multi-buy saves an additional 3 under these assumptions.
Check total spending and restrictions
If you need only one item, spending 60 on three may be less useful than buying one for 21. Storage, expiry and waste can change the practical value of a promotion. The discount calculator can verify an equivalent percentage but cannot assess product quality, eligibility or how a refund will allocate the discount. Compare tax and shipping separately and read whether the promotion requires membership or excludes particular products.
Try the calculators
- Discount calculator
Find the sale price and how much you save.
- Average & median
Find the mean, median and sum of a list.
- Percentage calculator
Find a percentage of any number.