About BidBut.com

BidBut.com is a small, independent site built around six free calculators for people who bid in online auctions and hunt for resale deals. There’s no company history to tell here — just a walk through what each tool does and why it exists.

Setting a ceiling before you bid

The Max Bid Calculatorstarts from your total budget and works backwards — subtracting shipping, sales tax, and any buyer’s premium or platform fee — to show the highest hammer bid you can actually place, and the all-in cost if you win at that bid. It exists because it’s easy to win an auction and still lose money once the fees get added afterward.

The Auction Fee Calculatorruns the same math from both directions: a seller’s net proceeds after final-value and payment fees, and a buyer’s all-in cost with shipping and buyer’s premium included, with a full line-by-line breakdown of where the money goes.

Playing the clock during the auction

The Bid Increment Calculator takes the current high bid and returns the next minimum bid, using a documented eBay-style increment tier table, plus a few steps further out so you can see roughly where a bidding war is headed before you commit to it.

The Snipe Timing Calculator takes the auction’s close time and your lead time in seconds and gives you the exact moment to place a snipe bid, with a countdown to both your bid and the close, measured against your own reference time.

Checking whether the win was actually a win

The Deal Savings Calculator compares a list price against a sale or auction price, stacks in a coupon if there is one, and returns the amount saved, the savings percentage, the final price, and the price per unit — with a check against whatever discount you were actually aiming for.

The Landed Cost Calculator adds item price, shipping, import duty or tax, and handling to show the true delivered cost of a win, and lets you compare two listings side by side so you can see whether the cheap item plus shipping actually beats the pricier one with free shipping.

Beyond the calculators

The Museum of Auctions & Trade is a separate, browsable section covering the auction itself and how bidding works, the great marketplaces where goods have changed hands, the long story of money and value, and the treasures and collectibles that draw the highest bids. Every entry, image, and fact there is sourced from Wikipedia and Wikimedia Commons, not written by us. We also publish auction and deal-hunting articles on the blog and reference material under Learn.

What this site is and isn’t

BidBut.com is an independent, advertising-supported site. It isn’t affiliated with eBay, any other auction platform, or any brand mentioned in its guides. Every calculator runs on the numbers you enter and on documented conventions like eBay-style bid increment tiers — the results are estimates meant to help you plan, not a guarantee of what a platform will actually charge or how an auction will actually close. Fees, increments, and rules differ by marketplace, so always check the specifics on the actual auction site before you bid, and treat everything here as general information rather than financial advice.

Questions, a correction, or a tool idea? See Contact.