Auction Buyer Cost Calculator
Add buyer premium, auction fees, transfer tax and short-term finance to a hammer price to see the real cost of buying at auction.
💼 Are you a real estate agent or broker? Send this calculator to your buyers on your own branded listing page — every enquiry comes straight to your WhatsApp. Create free agent page →The hammer price is not the price. Buyers at auction pay a premium, an administration fee, the cost of the legal pack, transfer tax, and very often short-term finance because completion is typically required within a few weeks — far too fast for an ordinary mortgage.
Working the total out before bidding is what keeps a maximum bid honest, because everything above the hammer is fixed and unavoidable once the gavel falls.
What sits above the hammer
Buyer premium and transfer tax are percentages of the hammer price. The administration fee, legal costs and any short-term finance are separate. Finance is charged for every month until you refinance onto a normal mortgage, plus an arrangement fee on the whole facility.
Worked example
A 200,000 hammer price with a 2% buyer premium (4,000), a 1,500 admin fee, 1,500 of legal costs and 3% transfer tax (6,000). Borrowing 150,000 at 0.85% a month for three months with a 2% arrangement fee costs 6,825. The total is 219,825 — a 9.9% uplift on the hammer price.
Set the maximum bid net of all this
Decide the most the property is worth to you, subtract everything above, and bid to that number. Bidding to your valuation and discovering the costs afterwards is the single most common way auction buyers overpay.
Turn a calculation into an enquiry
Buyers who run these numbers are ready to talk. Give every listing its own page with your photo, phone and WhatsApp on it — leads land straight on your phone.
Create your free property pageFrequently asked questions
Why is short-term finance usually needed?
Because auction contracts typically require completion within twenty to twenty-eight days, which is faster than most mortgage applications complete. Buyers bridge and then refinance, or arrange a lender who works to auction timescales in advance.
Can I pull out after the hammer falls?
Generally not without losing the deposit and facing a claim for the shortfall on any resale. In most auction formats the contract is binding at the fall of the gavel, which is why the legal pack must be read before bidding.
What is in the legal pack?
Title documents, searches, special conditions of sale, leases and any tenancy details. It frequently contains conditions that shift costs to the buyer, so have a lawyer review it before the auction rather than after.