New auction buyers underestimate the total by 25–30% routinely. Not because the platform's hiding anything — every fee is shown before you bid. It's just that the hammer price is the start of the total, not the end of it.
Here's what stacks on top.
The hammer price
Your winning bid. That's all this is.
Buyer's premium
A percentage added to the hammer, paid by the buyer to the auction platform. Industry-standard for live and online auctions in the UK. Typical range: 15–25%.
Biddurs's default is 15%. Some events set higher (e.g. specialist sales). The number is always shown on the lot before you bid — there's a line that says "Buyer's premium: 15%" right under the bid box.
Why it exists: the seller pays a smaller commission, the platform covers the operating cost from the buyer side. It's the way the auction trade has worked for centuries; the percentages used to be lower but have crept up with the rise of online platforms.
VAT
Two layers possible:
1. VAT on the buyer's premium (always applies in the UK)
The premium is a service charge subject to VAT at the standard rate (currently 20%). So a 15% buyer's premium becomes ~18% in real cost.
2. VAT on the hammer price (depends on the lot)
This is where lots split:
- VAT-registered seller, no margin scheme. Hammer price has VAT added on top.
- Margin scheme (second-hand goods). The seller pays VAT only on their margin between cost and sale. As a buyer, you don't get a VAT receipt for the hammer, and you can't reclaim VAT on the hammer. The line just doesn't appear on your invoice. Most second-hand lots on Biddurs are sold under the margin scheme.
- Non-VAT-registered seller. No VAT on the hammer. Simple.
The lot listing tells you which applies, but if you're not sure, the rule of thumb is: if the lot is second-hand or a customer return, expect the margin scheme and no separate VAT line on the hammer. If it's sealed shelf-pull or new in box from a business seller, VAT may apply on top.
Shipping
Flat-rate per lot based on size:
- Small (up to 5kg): £4.99
- Medium (up to 17kg): £9.99
- Collection only (pallets, vehicles): £0 — but you collect from the warehouse
Won multiple lots and want them combined? Email us within 7 days of winning and we'll re-pack into one shipment and refund the postage difference. We don't auto-bundle because the alternative is over-quoting at checkout, which we'd rather not do.
Worked example: small electronics
You win an unsealed Nintendo Switch (margin scheme, second-hand) at £140 hammer:
Hammer: £140.00
Buyer's premium (15%): £21.00
VAT on premium (20%): £4.20
Shipping (small): £4.99
————————————————————————
Total: £170.19
You pay £170.19 for the £140 winning bid. There's no separate VAT line on the hammer because the lot is margin scheme. You can't reclaim any VAT — only £4.20 of VAT is on your invoice, and that's the bit on the premium.
Worked example: VAT on the hammer
You win a brand-new business-stock dehumidifier at £80 hammer, listed with "VAT added":
Hammer: £80.00
VAT on hammer (20%): £16.00
Buyer's premium (15%): £12.00
VAT on premium (20%): £2.40
Shipping (medium): £9.99
————————————————————————
Total: £120.39
You pay £120.39. If you're VAT-registered yourself, you can reclaim the £16 VAT on the hammer and the £2.40 VAT on the premium — net cost is £101.99. Keep the invoice.
Worked example: pallet at collection
You win an Amazon returns pallet at £150 hammer:
Hammer: £150.00
Buyer's premium (15%): £22.50
VAT on premium (20%): £4.50
Collection (no postage): £0.00
————————————————————————
Total: £177.00
You arrange to collect from the warehouse within 14 days. After 14 days a small storage fee per day kicks in.
Things people forget to factor in
- Petrol or van hire for collection-only lots. Some bidders win a pallet from a Manchester warehouse and only then realise they live in Cornwall.
- Reseller's time — sorting, photographing, listing on eBay/Vinted, packing, shipping. Easily £15/hour of labour you may or may not value into the total.
- Storage — until the stock moves, it's somewhere. Garage shelf, spare bedroom, lockup. Has a cost.
- Payment processor fees on resale — eBay takes ~13%. Vinted bundles it. Marketplace is free but slower.
The headline cost of a pallet often hides the real cost of a pallet by a factor of 2.
What's on your invoice
Every Biddurs invoice has these lines explicitly:
- One row per lot, with hammer price
- Subtotal
- Buyer's premium
- VAT (broken out separately)
- Shipping
- Total
You can download a copy via your account → Invoices page. Keep them — they're proof of purchase, and the VAT line is what you'd give your accountant if you're VAT-registered.
A rule of thumb
For mental arithmetic, a typical UK auction hammer-to-total conversion is about 1.22× — i.e. the total is roughly 22% higher than the hammer. So if you'd happily pay £100 all-in for an item, your max hammer should be £82, not £100.
The 22% varies a few points each way depending on shipping size and whether the hammer attracts VAT, but it's a useful default.