Bring a Trailer buyer fees: calculate the fee before bidding

By BidBud · October 19, 2026

Calculate the buyer fee separately from the hammer bid before deciding what you can spend. For a USD auction, the percentage, minimum and cap all matter. A flat “add five percent” shortcut can give the wrong answer at either end of the price range or in a different auction category.

This worksheet concentrates on the fee calculation. For registration, research and the broader buying process, start with our Bring a Trailer bidding guide.

Confirm the schedule on the actual listing

BaT’s current fee overview gives two schedules: 5% with a $250 minimum and $7,500 cap, or 10% with a $250 minimum and $4,000 cap. The buyer-fee FAQ identifies motorcycles, minibikes and scooters, parts and automobilia, wheels, ATVs, go-karts and tractors as 10% categories. Confirm the category and displayed fee before bidding.

The examples below use USD and exclude tax and other charges. Do not transplant these dollar amounts into a GBP or EUR listing. Check its bid confirmation and current local schedule instead.

Use the percentage, then apply the floor and cap

Let H be your proposed hammer bid, r the applicable rate, m the minimum and c the cap. The fee is:

Fee = smaller of c and the larger of m or (H × r).

Calculate the percentage first. If it is below the minimum, use the minimum. If it exceeds the cap, use the cap. Otherwise use the percentage result. Finally add the fee to the hammer bid. This subtotal still excludes your other acquisition costs.

Here are independently calculated examples for the 5% USD schedule:

• $3,000 hammer: 5% is $150, so the minimum makes the fee $250. Hammer plus fee is $3,250.
• $32,000 hammer: 5% is $1,600, between the floor and cap. Subtotal: $33,600.
• $150,000 hammer: 5% reaches the $7,500 cap. Subtotal: $157,500.
• $200,000 hammer: the uncapped percentage is $10,000, but the fee remains $7,500. Subtotal: $207,500.

For the 10% USD schedule, a hypothetical $12,000 hammer produces a $1,200 fee and $13,200 subtotal. At $40,000, the fee reaches its $4,000 cap. A $50,000 hammer therefore produces a $54,000 subtotal under that schedule.

Check what one more bid would cost

The extra cash required for a bid increase can exceed the increase itself. Within the uncapped 5% band, moving from $32,000 to $33,000 adds $1,000 to the hammer and $50 to the fee: $1,050 before other costs. Above the cap, moving from $200,000 to $201,000 adds $1,000 to that same subtotal because the fee stays capped.

At a boundary, calculate both totals rather than multiplying the increase by a blanket rate. Moving from $4,000 to $5,000 keeps the 5% schedule’s fee at $250. The subtotal increases by exactly $1,000. None of these examples determines the platform’s permitted next bid.

Keep a five-line fee record

Before you confirm a bid, write down:

1. Listing currency and auction category.
2. Proposed hammer amount.
3. Rate, minimum and cap checked against the listing.
4. Your calculated fee and the fee displayed by BaT.
5. Hammer-plus-fee subtotal, with remaining costs listed separately.

If your calculation and the confirmation disagree, pause and resolve the inputs. Common questions to check are whether you selected the right category, mixed currencies, omitted the minimum, or included another charge in a number labeled “fee.” Do not round a discrepancy away just to make the figures match.

Add the rest of your budget

Transport, inspection, title or registration, applicable taxes and repair allowances belong in separate budget entries. Confirm the amount and basis of each relevant charge for your purchase. An unknown cost is not a zero cost.

Use BidBud’s cost calculator to explore your own USD assumptions, then verify the auction’s displayed amounts before acting. BidBud is independent of Bring a Trailer and does not place bids.

Research checked October 19, 2026. All worked amounts are hypothetical arithmetic examples, not vehicle valuations, tax advice or a promise that fees will remain unchanged.