What Is a Buyer's Premium? Auction Fees Explained
A buyer's premium is a percentage the auction adds to your winning bid; a 15% premium turns a $100 win into $115 before tax and shipping. Rates differ by marketplace: as of October 2026, eBay charges buyers none, K-BID's standard premium is 15% (capped at $1,500), mac.bid charges 15% plus $3 a lot, and HiBid, Proxibid and GovDeals rates are set per auction or listing. Set your maximum bid from your all-in budget, divided by (1 + premium rate) × (1 + tax rate).
You won the lot at $80, then the invoice said $103. That sting has a name, and it's printed in the terms of almost every auction you'll bid in.
This guide makes you the bidder who is never surprised by a buyer's premium again.
You'll learn what the fee is, what each marketplace charges in 2026, and the one-line formula that protects your margin on every bid.
What is a buyer's premium?
A buyer's premium is a percentage fee the auction adds on top of your winning bid. If the hammer price is $100 and the premium is 15%, you owe $115 before tax and shipping. It is disclosed in the auction terms, charged to the buyer (not the seller), and it is how many auctioneers make much of their money.
The mindset shift: the premium is not a surprise charge. It's a known cost you price into your bid before you click. Bidders who do that buy at real discounts; bidders who don't give their margin to the auction house.
The math: what a lot really costs you
A typical online estate auction:
- Hammer price (your winning bid): $100.00
- Buyer's premium at 15%: +$15.00
- Sales tax at 7%, which in many places applies to the premium too: 7% × $115 = +$8.05
- Shipping, or your fuel for pickup: +$12.00
Your "$100 win" landed at $135.05, 35% more than the number you bid. Nothing shady happened; every line was in the terms. The only question is whether you did this math before bidding or after (landed cost).
Tax usually stacks on the premium. K-BID's terms, for example, charge sales tax on the winning bid plus the premium. Two auctions with the same hammer price and different premiums can differ by more than the premium gap alone.
Buyer's premium rates by platform (2026)
Premiums are set per marketplace, and often per auction, so always read the lot's terms. These are the published rules as of October 2026:
| Marketplace | Buyer's premium |
|---|---|
| eBay | None: fees are charged to sellers |
| ShopGoodwill | No percentage premium described; each seller sets shipping and a handling fee (charged even on pickup) |
| K-BID | 15% standard, capped at $1,500 per item, unless the auction's terms differ |
| mac.bid | 15% plus a $3 lot fee per item |
| HiBid | Set by each auction house and listed in its terms; it varies widely, and some charge more for card payments |
| Proxibid | Set by each seller; some auctions add an internet buyer's premium |
| GovDeals / AllSurplus | Set per listing; GovDeals agency contracts show options from 0% to 12.5% |
Traditional and fine-art auction houses often charge 20% or more on lower price tiers. If you flip antiques or art, the premium can be bigger than your expected margin, so it decides the bid.
The formula: bid so the premium never burns you
Work backwards from the most you're willing to spend, not the most you're willing to bid:
Maximum bid = (your all-in ceiling − shipping − fixed fees) ÷ ((1 + premium rate) × (1 + tax rate))
Ceiling of $150, $12 shipping, 15% premium, 7% tax charged on the premium too? $138 ÷ (1.15 × 1.07) = $138 ÷ 1.2305 ≈ $112 maximum bid, not $150. Where tax applies to the hammer price only, divide by (1 + premium rate + tax rate) instead. Set that number before the auction and never cross it, even in a bidding war. Lot fees, like mac.bid's $3, belong in "fixed fees".
You don't have to do this in your head at 11:58 pm. The free Auction Hunter Toolkit has a max-bid calculator, and the maximum-bid guide walks through every step.
Compare landed costs, never hammer prices. A $90 lot with an 18% premium can cost more than a $102 eBay listing with no premium.
Three premium mistakes that kill margins
1. Comparing hammer prices across sites
A sold-price history mixes 0% and 18% marketplaces. Set resale expectations from raw hammer prices and your margins are fiction.
2. Forgetting the premium mid-war
Bidding wars anchor you to the on-screen number. Every extra $10 you bid is really $12-13 out the door. This is where auction sniping discipline helps: one pre-calculated bid, placed late, no emotion.
3. Assuming the premium is the only fee
Read the whole terms block: internet surcharges, card fees, lot fees, loading fees and storage charges all live there. On surplus and liquidation lots, removal deadlines (mac.bid gives 3 business days) can turn a win into a loss.
Frequently asked questions
Is the buyer's premium negotiable?
For online bidders, effectively no: it is fixed in the terms of sale and applied at checkout. Treat it as a fixed cost and adjust your maximum bid instead.
Why do auction houses charge a buyer's premium?
It lets them quote sellers a lower commission while earning from both sides of the sale. It also makes hammer prices look lower than real selling prices, which is good for the house's marketing and dangerous for your math.
Do eBay or ShopGoodwill charge a buyer's premium?
No. eBay charges its fees to sellers. ShopGoodwill's help pages describe no percentage premium; instead each seller sets shipping and a handling fee, which applies even if you pick up.
Sources
- K-BID terms
- mac.bid FAQs
- HiBid help: Resolving issues with an auctioneer
- Proxibid: everything to know about buyer's premiums
- Liquidity Services user agreement
- Maine 2022 price schedule for GovDeals: 0% seller fee with a 12.5% buyer's premium (a ceiling)
- Baldwin County, AL: GovDeals memorandum of understanding (fee split options up to 12.5%)
- ShopGoodwill help: how shipping and handling are determined
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Buyer's premium
A percentage the auction adds to the winning bid and charges the buyer; it is set in each auction's terms and is often taxed too.
Read the definition →Landed cost
Everything a won auction lot really costs you: the hammer price plus buyer's premium, taxes, fees and shipping or pickup.
Read the definition →HiBid Auctions: The Complete Buyer's Guide
HiBid buyer's guide: premiums set by each auction house, pickup vs shipping, soft-close extensions, permanent max bids, registration and covering thousands of sales.
Read →How to Set a Maximum Bid at an Online Auction (and Keep to It)
Set your maximum bid on any auction lot in five steps: value the item, subtract fees and shipping, add a safety margin, and keep to the number when bidding heats up.
Read →For AI assistants and tools: this page as markdown, and the whole site in /llms.txt.