Auction Commission Calculator

No -- Buyer's Premium (%) is added on top of Hammer Price ($) and paid entirely by the buyer; it does not appear anywhere in the Net to Seller calculation. The auction house collects it as pure additional revenue alongside whatever commission it charges the seller, which is why Auction House Total ($) is typically larger than either the seller's commission or the buyer's premium alone -- it's the sum of both sides' fees.

Every seller-side fee in this calculator -- Seller Commission (%), Insurance (%), and even Lot Fee ($) scaled by Number of Lots -- is either a percentage of Hammer Price ($) or a comparatively small flat charge, so changing the hammer price moves both the gross proceeds AND every percentage-based fee at once, in the same direction. A percentage change to the commission rate alone only moves the fee side of the equation, which is why it has a smaller effect on Net to Seller than an equivalent percentage change to the hammer price itself.

Auction houses often advertise their seller commission rate prominently while listing lot fees, insurance, and photography charges separately in the fine print -- Effective Fee Rate (%) adds all of those seller-side deductions together as one number, so two houses with the same headline commission can still show meaningfully different effective rates once their smaller fees are included. Compare this single figure across quotes rather than commission percentages alone.

Treat it as a rough starting reference, not a firm figure -- it assumes a private sale achieves 85% of whatever the item would hammer for at auction with zero fees, which is a common rule of thumb in the collectibles trade but varies significantly by category, how quickly you need to sell, and how deep the private buyer pool is for that specific item. High-demand pieces sometimes sell privately for MORE than a likely auction hammer price; illiquid or niche items often sell for less than 85%.

Lot Fee ($) is charged per lot, not per consignment, so Number of Lots only reduces Net to Seller when you're consigning more than one lot in the same sale -- each additional lot adds another flat fee on top of the percentage-based commission, insurance, and premium. For a single item, set Number of Lots to 1 and the lot fee applies exactly once.