CoinHub LabsValue & Bullion / Free

Coin Auction Bid Planner

Know your limit before the next lot.

One auction. One budget. Count the buyer fees and every active bid, not just the coin you hope to win.

01 / Auction termsUSD only

Plan name

Invoice budget ($) Keep unspent ($) Buyer premium (%) Minimum per lot ($)

Tax, shipping & other costs

Invoice shipping ($) Other invoice costs ($) Bidding surcharge (%) Estimated tax (%) Tax applies to

Also estimate tax on shipping & other invoice costs

Enter your budget and the sale's terms.

03 / Your lots

Keep the whole auction in view.

No lots yet.

04 / Before another bid

What is my next limit?

Candidate lot

Maximum hammer / entered step--

Add a lot and complete the terms.

This is a planning ceiling, not a valuation or a winning-bid prediction. The step rounds down on a simple grid from zero; real auctions can use variable increments and proxy rules.

Drafts stay in this tab. Downloads contain your lot names and costs; keep them private.

Existing CoinHub account

Saved plans

Private to your account

Existing confirmed CoinHub accounts only. Your draft stays in this tab until you choose to save it.

Not connected. No new account or email is created here.

From a hammer price to an honest auction budget

A hammer price is the winning bid, not necessarily the invoice total. A buyer premium may have a minimum on each lot. Shipping may be shared across an invoice. This worksheet keeps those different costs separate, then adds every active bid and won lot to show the exposure if all active bids win.

Set a limit before placing the next bid

Enter the terms for one auction invoice in U.S. dollars. Mark lots Watching until you actually submit a bid, then Active. Mark a won lot Won and enter its actual hammer. Use Lost only after you verify that the commitment has ended. Two alternative coins can both be won; they both remain in the active total.

The maximum-hammer calculation subtracts your reserve, shared invoice charges and other active/won lots from the budget. It then finds the largest entered-step hammer whose lot cost fits the remaining amount and any optional per-lot cap. With an illustrative 20% premium, no tax, $10 shared shipping and a $130 budget, a $100 hammer fits exactly. Real sale terms may differ.

What the estimate does not decide

Premium = the larger of your percentage of hammer or the entered minimum. The optional surcharge is a percentage of hammer. Tax uses your selected basis; each fee and tax rounds up to cents. Shared charges are added once if there is a commitment. The unspent reserve is excluded from spending, not charged by the auction.

Blank shipping remains unknown. The planner does not determine tax law, exemptions, foreign exchange, tiered fees, import duties, payment eligibility, coin authenticity or market value. Use separate plans for different invoices/currencies. Confirm the actual fee schedule and shipping quote before bidding; the auction's final invoice controls.

Research a coin's comparable sales in Value Evidence Desk. For bullion, compare premiums over metal value. For seller proceeds rather than buying costs, use the Coin Selling Fees Calculator.

Methods checked October 24, 2026 against GreatCollections' buyer-fee and invoice terms and Heritage's explanation of proxy bidding. No auction is affiliated with this planner. Example rates are illustrative, not current house quotes.