How much deposit do I need at auction?

Standard is 10% of the hammer price, payable on the day (usually via bank cheque or transfer). Some agents accept 5% by negotiation. The balance comes from your mortgage at settlement (typically 42-90 days later).

Is there a cooling-off period after auction?

No. Auction purchases are unconditional — no cooling-off, no subject-to-finance. That's why you must have pre-approval, building inspection, and contract review done BEFORE auction day. If the hammer falls on your bid, you're legally bound.

What happens if the property is passed in?

If bidding doesn't reach the vendor's reserve, the property is 'passed in'. The highest bidder gets first right to negotiate privately with the vendor. This can actually be advantageous — you can add conditions (finance, inspection) that aren't available at auction.

§ Tool · tier 1 · independent

Auction Bidding Calculator.

Calculate your maximum auction bid including stamp duty, conveyancing, and inspection costs. Know your true budget before the hammer falls.

CalculatorFree, no signupOn-deviceupd August 2026

Inputs

Your numbers

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Move the sliders or type in the form on the left — the math updates live as you go. Click Get AI verdict when you want a written analysis.

Auctions are high-pressure — the auctioneer is working against you, and it's easy to bid $20,000-$50,000 more than you can afford in the heat of the moment. The key to winning is knowing your absolute maximum bid BEFORE you arrive, accounting for stamp duty, conveyancing, inspections, and the deposit gap. This calculator works backwards from your budget to give you a precise maximum bid — so you can bid confidently without risking financial stress.

§ Worked examples

Real-world scenarios

First Home Buyer — Sydney

Budget: $900K. Deposit: $180K. Pre-approval: $720K. First home buyer in NSW.

Maximum bid: $800,000. Stamp duty: $0 (full first-home-buyer exemption — NSW's FHB threshold is $800K). Legal/inspection: $3,300. Deposit needed on the day (10%): $80,000. Remaining cash after deposit + costs: ~$96,700 (buffer). Here the $720K pre-approval — not the cash deposit — is the binding constraint; a bigger pre-approval would let the buyer bid past $800K before stamp duty starts applying on a sliding scale up to $1M.

§ FAQ

Questions Australians ask

§ Glossary

Plain-English definitions

Reserve Price

The minimum price the vendor will accept. Not disclosed publicly. If bidding doesn't reach the reserve, the property is passed in.

Passed In

When bidding at auction doesn't reach the vendor's reserve price. The highest bidder gets first right to negotiate.

Vendor Bid

A bid made by the auctioneer on behalf of the seller to advance bidding. Must be declared and is only allowed before the reserve is met.

§ Pair it with

Related tools

Stamp Duty Comparison

Compare stamp duty across states before planning your bid.

Borrowing Power Calculator

Find your maximum loan amount to set your auction budget.

Property Settlement Calculator

Full settlement cost breakdown after winning at auction.

How to use

01Enter your total property budget (deposit + loan pre-approval).
02Add your available deposit cash.
03Select your state for stamp duty calculations.
04Choose your buyer type for applicable concessions.
05Enter your loan pre-approval amount.
06Get your maximum bid, required deposit, and a bid ladder showing increments.

Key info

At auction you usually need a 10% deposit on the day (or 5% with negotiation).
Stamp duty, conveyancing ($1,500-$3,000), and inspections ($500-$1,500) must come from your cash — not the loan.
Your maximum bid = Total budget − stamp duty − legal costs − inspection costs.
If your maximum bid x 10% exceeds your cash deposit, your max bid is deposit-limited.
First home buyers may get stamp duty exemptions that raise their max bid.

Pro tips

Write your maximum bid on your hand or a card — never go above it no matter what.
Budget for building & pest inspection ($500-$1,500) BEFORE the auction — once the hammer falls, there's no cooling-off period.
Ask the agent for a vendor statement/contract review by your solicitor before auction ($200-$500).
If your bid is $5K below someone else's, a strategic $1K increment can pressure them into stopping.

Avoid these

Bidding your entire budget without allowing for stamp duty and legal costs — you'll be short $30,000+.
Not getting a building inspection before auction — no cooling-off period means you're stuck with defects.
Emotional overbidding — FOMO is the most expensive emotion in real estate.
Forgetting that the 10% deposit is due immediately — you need cleared funds on auction day.

Disclaimer: Estimates only. Interest rates, fees and policies change frequently. Always verify with lenders directly. General information, not personal financial advice.

Last updated · August 2026