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.

Auction Bidding Calculator

Calculator

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

Free to useNo data storedAI insightsUpdated: February 2026

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.

Enter Your Details

Real-World Examples

First Home Buyer — Sydney

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

Maximum bid: ~$842,000. Stamp duty: ~$33,340. Legal/inspection: ~$4,500. Deposit needed on the day (10%): ~$84,200. Remaining cash after deposit + costs: ~$58,000 (buffer). With FHB concession on homes under $800K, bid limit could rise to ~$860,000 if targeting sub-$800K range.

Frequently Asked Questions

Glossary

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.

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

1Enter your total property budget (deposit + loan pre-approval).
2Add your available deposit cash.
3Select your state for stamp duty calculations.
4Choose your buyer type for applicable concessions.
5Enter your loan pre-approval amount.
6Get your maximum bid, required deposit, and a bid ladder showing increments.

Key Information

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 Mistakes

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: This calculator provides estimates only and should not be relied upon for financial decisions. Interest rates, fees, and policies change frequently. Always verify information with lenders directly. This is general information, not personal financial advice. Consider seeking advice from a licensed mortgage broker or financial advisor.

Last updated: February 2026