Buyer's Premium Confirmation Tool
FAQ
What does the buyer's premium confirmation tool do?
The tool confirms whether a price can already include a buyer's premium based on the auction bid increment. It also calculates the buyer's premium amount and the total price if the premium still needs to be added.
What should I enter as the hammer price?
Enter the price you want to test. This might be a reported auction sale price, a hammer price from an invoice, or another amount you are trying to classify as either pre-premium or premium-included.
What is the buyer's premium percentage?
The buyer's premium percentage is the fee added by the auction house to the hammer price. For example, if an item sells for a $100 hammer price and the buyer's premium is 20%, the premium is $20 and the total is $120 before any other taxes or fees.
What is a bid increment?
A bid increment is the step used for valid bids in an auction. If the bid increment is $5, valid hammer prices might be $5, $10, $15, $20, and so on. The calculator uses this to decide whether a backed-out pre-premium amount looks like a valid auction bid.
What does a positive result mean?
A positive result means the entered amount can include buyer's premium because the pre-premium amount backs into a valid bid increment. For example, $12 with a 20% buyer's premium and a $5 bid increment backs into a $10 hammer price.
What does a negative result mean?
A negative result means the entered amount does not appear to include buyer's premium under the bid increment you entered. The tool will show the premium that would be added if the entered amount is treated as the hammer price.
What does "could be either" mean?
Some amounts can be both a valid hammer price and a valid premium-included total. In that case, the calculator cannot determine the auction's pricing convention from one item alone. Try the calculator on another item from the same auction to help verify whether reported prices include buyer's premium.
Can this help with fair market value research?
Yes. Auctioneers, appraisers, dealers, bidders, and estate professionals can use the tool to review auction results, compare sale prices, estimate buyer's premium, and document pricing assumptions for fair market value research or resale analysis.
Does this include sales tax or other fees?
No. The calculator only evaluates buyer's premium against the entered hammer price, premium percentage, and bid increment. Auction houses may also charge taxes, shipping, handling, platform fees, or other charges that are not included here.
Why might results differ between auction houses and third-party aggregators?
Lot information received directly from an auction house may report hammer prices, buyer's premiums, and totals differently than a third-party auction aggregate. Some aggregates may display a price that already includes a buyer's premium from an auction house, while also showing a buyer's premium percentage as if a buyer had bid through the aggregate. Because of these reporting differences, the calculator may be inaccurate if the hammer price you enter already includes a buyer's premium that does not match the buyer's premium reported by the third-party aggregate.
Should I rely on this instead of the auction terms?
No. The tool is a convenience for checking auction math. Always verify calculations against the auction listing, bidder agreement, invoice, or auction house terms.