Buy 2 Get 1 Free Calculator

Buy 2 get 1 free: what you pay per item

Buy 2 get 1 free is the grocery store version of a percentage discount with a minimum purchase attached. You have to buy three items, and one of them is free, so the discount on the basket is one third. On a $5 item that is $10 for three items instead of $15, which works out to $3.33 each.

The number worth comparing is the price per item after the deal. A 3 for 2 offer on a $5 item lands at $3.33 per item. The same item on a buy 1 get 1 free offer lands at $2.50, because that deal is a 50% discount rather than 33.3%. The tier matters as much as the price.

The calculator shows how many items you get, the full basket price, what you pay, the discount percentage and the cost of each item. It also compares the deal against buying only what you need, which is the check that separates a real saving from a larger purchase.

Because the offer is built around a group of three, it also lets you change the tier. Enter how many you buy and how many come free, and the same math covers 3 for 2, 5 for 3, 4 for 3 and any other combination a shelf tag throws at you.

Multi-buy tiers compared

Shelf tags use tiers rather than percentages, which makes them hard to compare at a glance. The table below converts the common ones on a $5 item.

The rule behind the table is short. Divide the number of free items by the total number of items and you have the discount. Buy 2 get 1 free is 1 out of 3. Buy 3 get 2 free is 2 out of 5. That is why 3 for 2 sits at 33.3% and 5 for 3 sits at 40%.

The basket size rises with the discount, and that is the trade. A 50% deal needs two items, a 40% deal needs five, and a 33.3% deal needs three. The best discount is not always the best offer if the larger basket pushes you past what you will use.

Worked example: $5 items on a 3 for 2 deal

Take the default inputs: a $5 item, a buy 2 get 1 free offer, one set, and a shopper who needs three items.

• Items per set: 2 bought + 1 free = 3
• Items you get: 3
• Full price without the deal: $15.00
• You pay: $10.00
• You save: $5.00
• Discount: 33.3%
• Price per item: $3.33
• Cost of buying three at full price: $15.00
• Deal versus buying what you need: saves $5.00

The shopper needed three items, so the deal delivers a genuine $5 saving. Change the need to two items and the same deal costs $10 for three when two would have cost $10, so the saving disappears and the shopper ends up with an extra item.

Now switch the tier to buy 3 get 2 free on the same $5 item. Five items would cost $25 at full price and $15 on the deal, a saving of $10 and a price of $3.00 per item. The discount rises to 40%, but the basket rises from three items to five, and the shopper has to be confident they will use all five.

Buying more sets and the unit price

Multi-buy deals stack by set, and the price per item does not change when you buy more than one set. Two sets of a 3 for 2 deal on a $5 item gives six items for $20, which is still $3.33 each. The discount percentage is fixed by the tier, so buying more sets multiplies the saving without improving the rate.

An $8.99 item shows the arithmetic on a realistic grocery price. One set of 3 for 2 gives three items for $17.98, or $5.99 each. Two sets give six items for $35.96, a saving of $17.98 against the $53.94 full price. The rate stays at 33.3% in both cases.

That is the useful thing to understand about tiers. The percentage is a property of the offer, not the quantity. Buying more sets changes the size of the saving and nothing else, so the only question that matters is whether you will use the extra items before they go off.

Where the offer does change is at the margin. Some stores require the free item to be the cheapest in the group, which lowers the effective discount if you mix prices. If the free item is a $5 product rather than a $12 one, the real saving on a mixed basket is smaller than the tag suggests, and the price per item is higher than the calculator shows for a uniform basket.

When a 3 for 2 beats a straight discount

A 3 for 2 deal and a 33% off sign are close to the same offer, and there is one clear case where the multi-buy wins: when you would have bought three anyway. In that case the deal and the discount are equivalent, and the deal is the one that appears on the shelf.

The case where the multi-buy loses is when the third item is optional. A straight 33% off lets you buy two items at two thirds of the price and pay $6.67 on a $5 item basket of two. The 3 for 2 deal forces the third item, so the minimum spend is $10 instead of $6.67. The percentage is the same and the cash outlay is not.

There is a third case worth knowing, where a straight discount beats both. If a store offers 40% off a single item, it is better than a 3 for 2 deal at 33.3% and it carries no minimum. Multi-buy tiers are a way of framing a discount around a larger purchase, and a plain percentage on one item is usually the cleaner offer.

The practical rule is to compare the price per item with the deal and without it, then decide whether you need the quantity. The calculator gives you both numbers, and the need field turns the comparison into a single line.

Shelf tags, expiry dates and what to check

Multi-buy offers carry more fine print than a simple price cut, and three lines matter most. The free item is often the lowest priced one in the group. The deal may apply per transaction, which caps the number of sets you can buy in one visit. And some stores exclude items that already carry a markdown, which removes the stacking that makes a tier genuinely cheap.

Expiry dates decide whether the saving survives. On canned goods, pasta, cleaning supplies and frozen food, a 3 for 2 deal is close to free money. On bread, dairy, fresh meat and produce, the third item is a race against the fridge, and a wasted item turns a 33.3% saving into a loss equal to the full price of one item.

Prices also move, which changes whether a deal is worth taking at all. The Bureau of Labor Statistics price index tracks grocery prices month by month, so a tier that was a good deal last year may sit above today's everyday price. Comparing the unit price across visits is the reliable test.

If a promotion looks misleading, the standard a retailer is expected to meet is set out in the FTC's rules on deceptive pricing. The unit price on the shelf tag is the figure to check, and it should reflect the deal rather than the pre-deal price.