BOGO CalculatorBuy one get one deals turned into a real % off
A BOGO calculator converts “buy one, get one” offers into a real percentage discount and price per item. Buy one get one free is 50% off both items, but buy one get one 50% off is only 25% off: $40 + $20 = $60 for $80 of goods.
- 7 deal presets + custom
- Lesser-value rule
- Do-you-need-it check
- Price per item
By Manzoor Ahmad · 13+ years of web development & SEO · Updated October 25, 2026Set up the deal
What Does BOGO Mean?
BOGO means “buy one, get one”: you pay full price for one item and get a second item free or at a discount. “Buy one get one free” is 50% off both items, but “buy one get one 50% off” is only 25% off overall. The real discount is Value of the discount ÷ Full price of every item in the deal.
Every BOGO Deal Converted to a Real Discount
All items priced at $20 each. The last column is the percentage you would need on a normal sale sign to match the deal.
| Deal | Items | You pay | Per item | Real discount |
|---|---|---|---|---|
| Buy 1, get 1 free | 2 | $20.00 | $10.00 | 50% |
| Buy 1, get 1 50% off | 2 | $30.00 | $15.00 | 25% |
| Buy 1, get 1 25% off | 2 | $35.00 | $17.50 | 12.5% |
| Buy 2, get 1 free | 3 | $40.00 | $13.33 | 33.3% |
| Buy 3, get 1 free | 4 | $60.00 | $15.00 | 25% |
| Buy 2, get 1 50% off | 3 | $50.00 | $16.67 | 16.7% |
| Buy 2, get 2 free | 4 | $40.00 | $10.00 | 50% |
BOGO Formula
What you pay
Pay = X × Price + Y × Price₂ × (1 − d)Buy X at full price, get Y at d% off. BOGO 50%: 1 × $40 + 1 × $40 × 0.5 = $60.
Real discount
Real % = Y × Price₂ × d ÷ (X × Price + Y × Price₂)$20 ÷ $80 = 25% off.
Example: Buy One Get One 50% Off $40 Shoes
- Full-price pair: $40.00.
- Second pair at 50% off: $40 × 0.50 = $20.00.
- Total: $60 for two pairs worth $80, a saving of $20.
- Real discount: $20 ÷ $80 = 25%, or $30 per pair.
- If you only needed one pair: you spent $20 more than planned to “save” $20.
The “Lesser Value” Rule
Most BOGO offers say the free or discounted item must be of equal or lesser value. If you pick a $50 item and a $30 item on “buy one get one free”, the store makes the $30 item free, not the $50 one. Enter the cheaper price in the “discounted item” field to see the real result.
Pair similar prices
Two items close in price give the biggest real discount, up to the full advertised rate.
Mixed prices shrink the deal
$50 + $30 on BOGO free is $50 for $80 of goods: 37.5% off, not 50%.
Tax on BOGO
Many states tax only what you pay on a store BOGO, but rules vary. Check with your state revenue department.
Is a BOGO Deal Worth It?
Worth it when…
You would buy the second item anyway, it keeps (toiletries, canned food, pet food, socks), or you can split it with a friend. Compare the per-item price with the Unit Price Calculator.
Skip it when…
You only need one, the item spoils, or a plain percent-off sale elsewhere gives a lower single price.
Related Shopping Calculators
Each of these answers the next question shoppers usually ask after this one.
Percent Off Calculator
Compare the BOGO per-item price with a plain percent-off sale on a single item.
Unit Price Calculator
BOGO packs and bulk sizes are easiest to compare by price per unit.
Double Discount Calculator
Adding a coupon on top of the BOGO? Combine the two discounts correctly.
Black Friday Calculator
Holiday doorbusters often use BOGO. Total them with your other deals and budget.
Discount Calculator
The main discount tool for percent, dollar, find-% and original price questions.
All Shopping Calculators
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BOGO Calculator FAQs
BOGO stands for “buy one, get one”. You buy one item at full price and get a second item free (BOGO free) or at a discount (for example BOGO 50% off).
Only if you want both items and they cost the same. Two $40 items for $40 is 50% off each. If you only needed one, you saved nothing.
You save 25% overall. Two $40 items cost $40 + $20 = $60 instead of $80.
Add the full price of the items you pay for to the discounted price of the free or reduced items, then divide the saving by the full value of every item. The calculator does this for any buy-X-get-Y offer.
It equals 33.3% off three items of the same price. That is better than BOGO 50% off (25%) but worse than BOGO free (50%).
The free or discounted item must cost the same or less than the item you pay for. When prices differ, the store discounts the cheaper item.
In many states, tax on a store BOGO is charged on the amount you actually pay. Some states and some manufacturer-funded offers are treated differently, so check your state’s rules.
Compare the per-item price. BOGO free on a $10 item gives $5 each; a 40% off sale gives $6 each but you only buy what you need. Use the Percent Off Calculator to compare.
Buy one get one 25% off is 12.5% off both items, because the $10 discount on a $40 item is spread over $80 of goods.
Some stores allow a coupon on top of a BOGO. The coupon usually applies to the total you pay. Combine them with the Double Discount Calculator.
Because you did. A BOGO raises the total bill to give a lower price per item. Use the “items you actually need” field to see whether the deal saves you money or just adds items.
Yes. It is free, needs no sign-up and runs privately in your browser.
Manzoor Ahmad
Founder of DexoCalc · 13+ years of web development & SEO experience
Manzoor built this BOGO calculator to show what multi-buy offers really cost. The deal decoder table and the items-you-need check come from the formulas on this page, and the lesser-value rule reflects how most retailers write their BOGO terms.
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Last reviewed and updated: October 25, 2026
Sources & References
- Federal Trade Commission — Guides Against Deceptive Pricing, 16 CFR 233.4 (“free” and two-for-one offers)
- Federal Trade Commission — Guide Concerning Use of the Word “Free” and Similar Representations, 16 CFR Part 251
- Tax Foundation — State and Local Sales Tax Rates
Disclaimer: results are estimates for planning and comparison. Store policies, coupon terms and local tax rules vary, so your receipt may differ. This calculator is not financial, legal or tax advice.