The three products side by side
Valuation
Registered valuer, physical inspection, documented comparable evidence, stated effective date, professional indemnity insurance, legally recognised. Typically $300–$600 residential.
Appraisal
Real estate agent, brief walk-through, no documented methodology, no professional liability, prepared to win a listing. Usually free.
Online estimate
Statistical model on recorded sales data, no inspection, no knowledge of condition or renovations, wide confidence range. Free.
Where each one is genuinely useful
An online estimate is a reasonable starting point for idle curiosity or for tracking a portfolio's rough direction. It cannot see that you renovated the kitchen, that the neighbour built a four-storey block over your northern aspect, or that your block has subdivision potential.
An agent's appraisal is genuinely useful for one thing: understanding what an agent thinks they can achieve in the current market, and how they intend to market it. Treat it as sales intelligence, which is what it is.
A valuation is what you need whenever a third party has to rely on the number: a lender, a court, the ATO, an auditor, a co-owner, an executor, or a business partner.
Why the difference exists in law
In Queensland, only a valuer registered under the Valuers Registration Act 1992 and listed with the Valuers Registration Board of Queensland may provide a property valuation. That restriction exists because a valuation carries consequences — loans are advanced on it, taxes are assessed on it, and estates and settlements are divided by it.
Registration brings obligations: professional standards, continuing education, professional indemnity insurance, and personal accountability for the figure. An agent providing an appraisal carries none of those in relation to the number they quote.
The conflict-of-interest point
An agent's income depends on winning and completing the sale. That is not dishonesty; it is a structural incentive, and it is why an appraisal is not independent evidence. Appraisals cluster optimistically at listing stage for exactly this reason.
A valuer is paid the same fee regardless of the figure and regardless of whether the property ever sells. There is no version of your valuation that pays us more, which is the entire basis on which lenders and courts rely on it.
When you have all three and they disagree
This happens constantly, and the spread is often 15 per cent or more. The resolution is not to average them. It is to identify which one is answering your actual question.
If you are choosing a listing price, the agent's number and the current buyer depth matter most. If you are refinancing, contesting a lender's figure, lodging a tax return or dividing an asset pool, only the valuation is relevant and the other two are noise.