About BogoDiscount

What this tool does

BogoDiscount computes the effective discount and per-unit cost for buy-one-get-one, buy-N-get-M, and percent-off-second-item promotions. It's designed for shoppers comparing offers in-aisle in a few seconds — punch in the prices, see the real unit price and the true percent off, and decide whether the deal is actually better than the plain ticket price.

How the math is verified

The arithmetic is straightforward — total cost divided by total items equals the effective unit price — but it's easy to fumble in your head when one item is half off and the other is full price. The calculator uses BigNumber for precision so rounding doesn't drift across multi-item promos, and every formula is cross-checked against worked examples on the page. If you spot a result that looks wrong, please email me — reader feedback has caught real bugs.

A note on appropriate use

This is straightforward shopping arithmetic. It doesn't model item-mix rules (different prices in a BOGO bundle where the cheaper item is the “free” one), sales tax, or store-specific stacking restrictions like coupon limits or loyalty-program multipliers. Read the fine print on the offer — the calculator gives you the math, not the policy.

About the author

Hi, I'm Jimmy Raymond. I built BogoDiscount as part of a small network of focused calculator sites I maintain. I hold a B.S. in Environmental Engineering and a B.S. in Computer Science from New Mexico Tech and the University of New Mexico, and my professional work has spanned safety-critical aerospace and space systems, real-time embedded software, and full-stack web development.

That background is where this site gets its design philosophy: the formula has to be correct, the assumptions have to be stated, and the limits of the tool have to be honest. I'm based in Albuquerque, New Mexico.

Contact

Email me at aj@ajdesigner.com for corrections, feature requests, or general feedback. You can also find me on LinkedIn.

— Jimmy