Auction fee & buyer's premium calculator
See what an auction bid will really cost: buyer's premium, VAT, delivery and currency, all in one total.
Some auction houses charge extra for bidding online rather than in the room, by phone, or absentee — commonly 3–5%.
| Bid amount | £0.00 |
| VAT on bid | £0.00 |
| Buyer's premium | £0.00 |
| Online bidding fee | £0.00 |
| VAT on fees | £0.00 |
| Delivery | £0.00 |
This calculator uses the figures you enter and is for guidance only. Confirm final costs with the auction house or seller before paying.
How BidCalc works out your total
At most auctions you pay more than the winning (hammer) price. BidCalc adds the extras for you, so you can see the real cost before you bid:
- Buyer's premium: a percentage of the hammer price that the auction house adds.
- Online bidding fee: an extra percentage some auction houses charge if you bid through an online platform.
- VAT: usually charged on the fees, and on the hammer price for some lots.
- Delivery: any fixed cost for packing, shipping or collection.
For example, an £800 hammer price with a 20% premium, a 4% online fee and VAT on the fees costs £1,030.40 in total. Enter the percentages from your own auction's conditions of sale to get your figure, or switch to "I have a budget" to find the highest bid you can afford.
Popular guides
- What is a buyer's premium?The fee added to your winning bid, with a worked example.
- Do you pay VAT on auction fees?"Plus VAT" vs "inclusive of VAT", and whether you can reclaim it.
- How to work out your maximum bidWork backwards from your budget, with the formula.
- Why is my invoice higher than my bid?Check every line of your auction invoice.
- Buyer's premium tableWhat £100 to £5,000 really costs at common rates.
- Copart UK fees explainedBuyer fee, bidding fee, lot fee and VAT.
Common questions
Is VAT charged on the buyer's premium?
Usually yes, either added on top ("plus VAT") or already included in the quoted rate. Check your auction's wording: if the premium is "inclusive of VAT", set the VAT box to 0% so it isn't counted twice. See the VAT guide.
How do I work out the most I can bid?
Switch to "I have a budget", enter your total, and BidCalc works backwards through the fees to your maximum hammer price. The maximum bid guide explains the formula.
Does BidCalc know my auction house's fees?
No. You enter the percentages from the auction's conditions of sale, so the result is always based on your own figures. The one exception is the Copart calculator, which has Copart UK's published fee tables built in.
Is BidCalc free?
Yes. It's free to use with no sign-up. The figures are guidance only, so always confirm the final costs with the auction house before you bid.