Gemsmakers · Antique Dealer Tools
Antique Auction Bid Increment Planner
Auction houses may use different increments at different bidding levels. Enter the exact increment schedule shown by the auctioneer, then use this planner to list upcoming bids and see how quickly bidding would reach your spending limit.
Calculator
Enter your figures below. Results update from the assumptions you supply; check your agreement, fee schedule, and local requirements before making a decision.
How to use this tool
- Enter current bid and maximum hammer-price budget.
- Enter one threshold and increment per line as: starting bid level | increment. Include a threshold of zero.
- Set how many upcoming bids you want listed. Review the next valid bids, each percentage increase, and the number of increment steps until the maximum is exceeded.
Calculation method
At each step, the calculator selects the increment attached to the highest threshold not exceeding the current bid, then adds that increment to produce the next bid. Percentage increase = increment ÷ current bid × 100; at a zero current bid the percentage is reported as not applicable.
Worked example
With a current bid of 480 and an increment of 25 at that level, the next bid is 505. If the maximum budget is 600, the schedule determines how many further steps remain using the increment table provided.
Important assumptions and limitations
- Always copy the auctioneer’s current increment schedule; it can change by auction or lot.
- This tool calculates hammer bids only and does not include premium, tax, shipping, or restoration. Use the maximum-bid calculator for landed-cost limits.
- Some auctions allow increments or bids that differ from the posted schedule at the auctioneer’s discretion.
Frequently asked questions
Does this calculate the buyer’s premium?
No. It plans hammer-price increments. Buyer premium and other charges should be considered separately when setting the maximum hammer budget.
What if the maximum is below the current bid?
The tool will warn that the entered budget has already been exceeded.
Why include thresholds?
The increment often increases as bidding rises; thresholds tell the calculator which increment applies at each bid level.
Should I enter the next increment or current level?
Enter each threshold as the bid level at which that increment starts applying, based on the auctioneer’s posted table.
Can I trust it for every auction?
Use it as a planning aid only. The auctioneer’s announced terms and actual accepted bids control.
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