The room has a fixed bidding capacity. The format determines how much of it gets unlocked. The item category determines whether each lot hammers above or below fair market value. Starting bids that are too low ruin lots that would otherwise be the night's stars. Most auction chairs design the item portfolio by what got donated — not by what the room can absorb. This tool models the expected hammer per item, the format-by-format yield, and the mix optimization.
The room sets the bidding capacity. The format decides how much of it the auction can unlock. A 200-person UHNW room can absorb $250-400K of auction; the same room with the wrong items and a weak auctioneer will produce $60K.
The silent auction is a volume game. 20-50 items, each opening at 30-40% of FMV, closing at 65-95% of FMV with mobile bidding, 50-75% with paper sheets. Categories matter enormously.
5-8 live lots, ideally. Each one is its own three-minute mini-event. Live items hammer above FMV when they are genuinely scarce — and below FMV when they're commodity travel/sports packages that anyone could buy online.
The single highest-yield 10 minutes of any gala. Paddle raise (fund-a-need) directly asks for cash gifts at named giving levels. With a professional auctioneer and pre-arranged top-tier bids, paddle raise often equals or exceeds the entire live auction.
Item-by-item hammer ratio, format yield breakdown, room-capacity analysis, and the mix-optimization recommendations.
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Educational and informational purposes only. This calculator and any output it produces are intended solely for general educational and decision-support purposes. They do not constitute investment, tax, legal, accounting, appraisal, lending, insurance, or any other professional advice.
Estimates based on your inputs. Auction outcomes depend on factors no model can capture (room energy, auctioneer skill on the night, mission moment delivery, weather, news cycle). Use these outputs as planning guidance, not as a fundraising commitment. Charity auction items have specific IRS disclosure rules — items sold above FMV produce only the difference as a deductible contribution for the bidder; charities must disclose item FMV at bidding (Pub. 526, Pub. 1771).
Consult your own qualified professionals. Before acting on anything calculated here, consult your own attorney, CPA, or qualified appraiser as applicable.
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