How to compare builder quotes for a renovation and pick the best fit

To compare renovation quotes properly, make them describe the same job first, then compare price. Give every builder the same drawings, specification and finish schedule; convert every figure to GST-inclusive dollars; adjust for exclusions and for prime cost and provisional sums that are set too low; and check licence, insurance, deposit and payment terms. The quote that is the best fit is the one that covers your scope with realistic allowances, fair payment terms and a licensed, insured builder, which is not always the lowest number on the page.

This guide is part of worked estimates and checklists. Use the quote comparison checklist as you go.

Step 1: send the same brief to every builder

Quotes diverge most when the brief is vague. Before asking for quotes, prepare:

drawings, even simple measured sketches for small jobs;
a written scope for each room;
a finish schedule naming tile type, tapware range, cabinetry finish and appliance models, or an allowance for each;
known site conditions: access, parking, asbestos test results, strata rules.

Ask for an itemised quote rather than a single lump sum. A builder who will only give a lump sum makes it hard to price variations later.

Step 2: normalise the numbers

Adjustment	How to do it	Example (illustrative)
GST	Convert ex-GST figures by adding 10%	$40,000 + GST becomes $44,000
Exclusions	Add your own estimate for anything excluded	Waste removal excluded: add $1,500
Low allowances	Replace each PC or provisional sum with a realistic figure	Tile allowance $2,000 vs expected $4,000: add $2,000 plus margin
Owner-supplied items	Add the cost of items you would have to buy	Appliances "by owner": add their cost
Approvals	Add council or certifier fees if excluded	Add $2,500

Worked comparison (illustrative)

Three quotes for the same mid-range bathroom and laundry.

Item	Quote A	Quote B	Quote C
Headline price	$52,000 incl. GST	$43,000 + GST	$47,000 incl. GST
GST adjustment	$0	+$4,300	$0
Waste removal	Included	Included	Excluded, +$1,500
Tile allowance (expect $4,000)	$4,000, +$0	$3,500, +$550	$2,000, +$2,200
Tapware allowance (expect $2,500)	$2,500, +$0	$2,500, +$0	$1,500, +$1,100
Adjusted comparison price	$52,000	$47,850	$51,800

Allowance shortfalls are increased by an illustrative 10% builder's margin, which is how many contracts charge for PC and provisional sum overruns: for example ($4,000 − $3,500) x 1.1 = $550 and ($4,000 − $2,000) x 1.1 = $2,200. Quote C looked $5,000 cheaper than A but is only $200 cheaper once adjusted. Quote B is now the lowest, by about $4,000. Check the margin rate stated in each contract rather than assuming 10%.

Next, check the non-price items.

Step 3: compare the terms, not just the price

Term	What good looks like	Red flag
Licence or registration	Number on the quote, matches the register in the contracting entity's name	No number, or a number in someone else's name
Home warranty insurance	Certificate before deposit where required	"We don't need it for this job" on a job above the threshold
Deposit	Within the state cap	Asking for more than the cap, or "materials deposit" on top
Progress payments	Tied to completed stages	Large payments early, before work is done
Start date and duration	Stated in writing	"As soon as possible"
Variations	Written, priced and signed before work	"We'll sort it out at the end"
Defects	Clear process and statutory warranty explained	No mention

State caps and thresholds are in renovation rules by state. Deposit and payment details are in deposits and progress payments.

Step 4: check the builder

Search the licence register in your state and confirm the class of licence covers the work. See how to check a builder's licence.
Check the ABN on the Australian Business Register and whether the business is registered for GST.
Ask for addresses of recent similar jobs you can look at from the street.
Ask who will supervise the work day to day.

Avoid relying on online star ratings alone. They are not verified, and a regulator's register tells you more about licence status and disciplinary history.

Step 5: decide on best fit

Use your own weights. For example: price after adjustments, completeness of scope, payment terms, start date, and your confidence in communication. A slightly dearer quote with a firm programme and realistic allowances is often cheaper in the end than a low quote that relies on variations.

Mistakes to avoid

Comparing headline prices without adjusting for GST and allowances.
Accepting a quote that is far below the others without asking what is missing.
Signing a quote instead of a contract. In NSW, a quote alone does not meet the written contract requirements for work over $5,000.
Paying a "booking fee" to hold a start date that bypasses deposit caps.

FAQ

How many quotes should I get?

Two or three is common for renovations. More than that takes builders' time and often adds little if the brief is clear.

Should I pay for a quote?

Some builders charge for detailed quotes or preliminary design. If so, agree in writing what you get and whether it is credited against the contract. Victoria's 2025 reforms allow separate preliminary agreements for plans and specifications once they commence.

Can I negotiate?

Yes. Negotiate scope and allowances rather than squeezing margin, which can lead to corner-cutting.

What if a builder will not itemise?

Ask for at least a breakdown by trade. If they still refuse, weigh that against the risk of disputes over variations.

Sources

Building Commission NSW, via NSW Government — contracts and choosing a builder in NSW
Building and Plumbing Commission (Victoria) — finding a registered practitioner
Queensland Building and Construction Commission — licensee register and contracts
Australian Business Register — ABN and GST registration lookup
Consumer Affairs Victoria — domestic building contract changes