Buy X Get Y Free Calculator
Compare paid and free units under a repeatable equal-price buy-X-get-Y promotion.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Break the desired received quantity into full promotion groups and a remainder.
Paid=floor(quantity/(buy+free))×buy+min(quantity mod(buy+free),buy)
Worked example
With buy 2 get 1 free at 20 each, receiving 5 items costs 80: four paid and one free. Receiving 6 items also costs 80: four paid and two free.
Assumptions and input details
All items have the same ordinary unit price and every complete group repeats without a limit. Quantity is received count, not paid count. Different-price cheapest-item rules, loyalty eligibility, purchase caps, stock, taxes and shipping are not assumed. Zero received quantity gives zero cost and an undefined per-item price.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
Compare product bundles by price per the same quantity. Mix compatible units, include multiple packs and view a ranked table and unit-price chart.
Combine consecutive percentage discounts, a fixed coupon, entered goods tax and shipping in a defined order.
Aggregate recipe demand, subtract available stock once and round shopping to whole packs.
Reserved advertising space.