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Buy X Get Y Free

Divide the free items by everything you carry home. Dividing by the items you paid for instead is how people end up calling BOGO “100% off”.

Your numbers

Real discount

33.3%

Price each

2,000

Saved

3,000

What it means

Buy-one-get-one is 50% off; two-for-three is 33.3%. This deal is 33.3%.

Formula

Real discount = Free items ÷ (Items paid for + Free items) × 100

If the extra spoils before you use it, the real saving is smaller than the number. Check that you can finish it first.

What to enter

InputDefaultAccepted range
Items paid forHow many you pay for; the free ones do not go here.21 and up
Free itemsHow many come free — one, in a buy-one-get-one.10 and up
PriceThe amount being charged. Decide first whether it is before or after tax.3,0000 and up

Step by step

FormulaReal discount = Free items ÷ (Items paid for + Free items) × 100
With the default numbersReal discount = 1 ÷ (2 + 1) × 100
AnswerReal discount = 33.3 %

Quick reference table

Results when only Items paid for changes and everything else stays put.

Items paid forReal discount (%)Price eachSaved
1501,5003,000
1.5401,8003,000
233.32,0003,000
3252,2503,000
4202,4003,000

What each result means

ResultAt default values
Real discount (%)Stacked discounts boiled down to one number — always less than adding them.33.3
Price eachWhat one costs, divided across everything you carry home.2,000
SavedHow much this deal keeps in your pocket.3,000

Common mistakes

If the extra spoils before you use it, the real saving is smaller than the number. Check that you can finish it first.

Glossary

Items paid for
How many you pay for; the free ones do not go here.
Free items
How many come free — one, in a buy-one-get-one.
Price
The amount being charged. Decide first whether it is before or after tax.
Real discount
Stacked discounts boiled down to one number — always less than adding them.
Price each
What one costs, divided across everything you carry home.
Saved
How much this deal keeps in your pocket.

Frequently asked questions

Q. How is Buy X Get Y Free calculated?

Real discount = Free items ÷ (Items paid for + Free items) × 100 — Divide the free items by everything you carry home. Dividing by the items you paid for instead is how people end up calling BOGO “100% off”.

Q. Can you walk through an example?

With Items paid for 2, Free items 1, Price 3,000, the answer is Real discount 33.3%.

Q. What do I need to enter?

Enter Items paid for, Free items, Price. The result recalculates as you type, and an empty box counts as zero.

Q. How much does the answer move if I change a number?

Changing only Items paid for moves the answer to Items paid for 1 → Real discount (%) 50 and Items paid for 4 → Real discount (%) 20. The table below lays out five steps.

Q. How are the numbers rounded?

Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.

Q. Anything to watch out for?

If the extra spoils before you use it, the real saving is smaller than the number. Check that you can finish it first.

Related calculators

Tax rates and interest conventions differ by country and product — check your contract for real transactions.