BOGO Calculator Formula
Understand the math behind the bogo calculator. Each variable explained with a worked example.
Formulas Used
Effective Price Per Item
effective_per_item = pair_cost / 2Total Cost
total_cost = pair_cost * num_pairsTotal Savings
total_savings = item_price * bogo_pct / 100 * num_pairsVariables
| Variable | Description | Default |
|---|---|---|
item_price | Item Price(USD) | 12.99 |
bogo_pct | Second Item Discount(%) | 50 |
num_pairs | Number of Pairs | 1 |
pair_cost | Derived value= item_price + item_price * (1 - bogo_pct / 100) | calculated |
How It Works
How BOGO Deals Work
Buy-one-get-one promotions give a discount on the second item when you buy two. The discount on the second item can range from a small percentage to 100% (completely free).
Formula
Pair Cost = Full Price + Full Price x (1 - BOGO Discount / 100)
Effective Per Item = Pair Cost / 2
Worked Example
A store offers BOGO 50% off on items priced $12.99. You buy 1 pair.
- 01First item: $12.99 at full price
- 02Second item: $12.99 x (1 - 0.50) = $6.50
- 03Pair cost = $12.99 + $6.50 = $19.49
- 04Effective per item = $19.49 / 2 = $9.74
- 05Savings = $12.99 x 0.50 = $6.50
Frequently Asked Questions
Is BOGO 50% the same as 25% off everything?
Yes, mathematically BOGO 50% off is equivalent to 25% off each item. The per-item effective discount is always half the BOGO percentage.
What does BOGO free mean?
BOGO free (or BOGO 100%) means you pay full price for one item and get the second at no charge. Your effective per-item cost is exactly half the retail price.
Do I have to buy exactly two items?
BOGO deals apply in pairs. If you buy an odd number, the last item is typically at full price. This calculator works in complete pairs.
Ready to run the numbers?
Open BOGO Calculator