GST & Buyer's Premium at Australian Auctions (2026): What You Actually Pay

The hammer price is never the whole story at an Australian auction. Two charges sit on top of your winning bid — GST and the buyer's premium — and getting them wrong is the most common way buyers blow their budget. This guide explains exactly how each works on Australian government and surplus platforms (Allbids, Pickles, Grays, Manheim) and how to calculate your true cost before you bid.

The Two Extra Costs

1. GST (Goods and Services Tax) — 10%. Australia's broad consumption tax. Whether it's already in the price or added on top depends on the lot.

2. Buyer's premium. A percentage fee the auctioneer charges the winning bidder on top of the hammer price. The rate varies by platform, category, and lot.

Get both into your maximum bid and you'll never be surprised at checkout.

GST-Inclusive vs GST-Exclusive — The Key Distinction

This is the single most important thing to understand about Australian auctions.

• **GST-inclusive lot:** the displayed/hammer price already contains the 10% GST. You don't add anything for GST.
• **GST-exclusive lot:** the displayed/hammer price is before GST. You add 10% on top.

Every lot's sale overview or terms states which applies. Government and commercial surplus can be sold either way, so check every time. A $10,000 bid is $10,000 on a GST-inclusive lot, but $11,000 on a GST-exclusive lot.

How Buyer's Premium Is Calculated

The buyer's premium is a percentage of the hammer price. On most Australian platforms the premium itself is GST-inclusive — the rate you see already contains GST.

There's an interaction with the lot's GST status:

• On a **GST-inclusive sale**, the premium is calculated on the GST-inclusive hammer price and is itself GST-inclusive.
• On a **GST-exclusive sale**, you typically pay GST on the buyer's premium as well, so factor that in.

Rates differ by platform and category — read each lot's terms rather than assuming a single number.

Worked Examples

• Hammer price: $10,000 (GST already included)
• Buyer's premium (5%, GST-inc): $500
• GST to add: $0
• **Total: $10,500**

• Hammer price: $10,000 (before GST)
• GST on lot (10%): $1,000
• Buyer's premium (5% on $10,000): $500
• GST on premium (10%): $50
• **Total: $11,550**

Same bid, same premium rate — but over $1,000 difference because of GST treatment. This is why checking the lot's GST status matters.

Can You Claim the GST Back?

If you're registered for GST and buying for business use, you can generally claim the GST as an input tax credit on your Business Activity Statement (BAS) — provided you hold a valid tax invoice for the purchase. The auctioneer issues the tax invoice on settlement. This effectively removes the 10% for eligible businesses. Private buyers cannot claim it back. Confirm your eligibility with your accountant or the ATO; this guide is general information, not tax advice.

Other Costs to Remember

GST and premium aren't the only add-ons. Depending on what you're buying:

• **Stamp duty / transfer duty** on vehicles, paid to your state road authority.
• **Registration and transfer fees**, plus a safety/roadworthy certificate if a vehicle is sold unregistered.
• **Storage fees** if you collect late.
• **Transport**, since most government surplus is collection-only.

Frequently Asked Questions

How much is GST at Australian auctions?

GST is 10%. On a GST-inclusive lot it's already in the price; on a GST-exclusive lot you add 10% on top of the hammer price. The lot's sale overview tells you which applies, so check before bidding.

What is a buyer's premium?

A fee the auctioneer charges the winning bidder on top of the hammer price, set as a percentage of the bid. It varies by platform, category, and lot. On most Australian platforms it's quoted GST-inclusive. Always read the lot terms for the exact rate.

Is the buyer's premium GST-inclusive in Australia?

Generally yes — Australian platforms like Allbids, Pickles, and Grays typically quote the premium GST-inclusive. However, on a GST-exclusive sale you may pay GST on the premium as well. The lot's terms specify the treatment.

How do I work out my true cost before bidding?

Start with your maximum hammer price. If the lot is GST-exclusive, add 10% GST. Add the buyer's premium (and GST on the premium for GST-exclusive sales). For vehicles, add stamp duty, transfer/registration, and transport. The total is your real cost — set your maximum bid so this number stays within budget.

Can I claim the GST back?

If you're registered for GST and buying for business purposes, you can generally claim the GST as an input tax credit on your BAS, provided you hold a valid tax invoice from the auctioneer. Private (non-business) buyers cannot. Check your specific situation with your accountant or the ATO.

Why is one auction GST-inclusive and another GST-exclusive?

It depends on the seller and the sale category. Government and commercial surplus can be sold either way. The displayed price and the lot's sale overview always state the GST treatment, so confirm it on every lot rather than assuming.

Do the same GST and premium rules apply to Allbids, Pickles, Grays, and Manheim?

The 10% GST rate is national, but each platform sets its own buyer's premium rates and may treat GST differently by category. The principles in this guide apply across all of them — but always read the specific lot's terms for the exact numbers.