You've got three quotes for your new home. One is $40,000 cheaper than the others. It's tempting to circle it and move on. Don't, at least not yet.
When you compare builder quotes, the bottom line is the least useful number on the page. Quotes differ because of scope, allowances, exclusions, site assumptions and contract terms, and most of those differences don't show up until you go line by line. Here's the method I use to turn three different prices into a fair comparison.
C4 - Asking the Right Questions Checklist
$59.00 AUD
Last updated 5 Oct 2026 · Revision 1 · Free updates for life
Checklist Type: Minor
Form Factor: Fillable, print-ready PDF (A4, 15 pages) plus the C4 Explainer PDF (35 pages)
When to use: Choosing a builder (before you pay a deposit or sign)
102 questions to ask every builder on your shortlist, including a visual check of one of their current sites. Compare like for like and choose your builder with confidence before you pay a deposit.
Why it's hard to compare builder quotes
Each builder writes its quote its own way. One includes the driveway; another leaves it out. One allows $3,000 for appliances; another allows $6,000. One assumes a flat block; another has allowed for rock.
The QBCC's own advice is to get more than one quote, ask each builder to price the same work, materials and timeline, and not decide on price alone. That's the whole game: make sure every builder is pricing the same house before you compare builder quotes on price.
Step 1: give every builder the same brief
The easiest comparison starts before the quotes arrive. Give each builder the same:
- Plans and specification, or the same written brief if they're using their own designs.
- Site information. Soil test, contour survey and any bushfire or flood information.
- Must-have inclusions, written down.
- Allowances you've set yourself, where you can (Step 3).
If something isn't in the brief, assume at least one builder won't price it.
Step 2: ask for a breakdown, not just a total
A single lump sum tells you nothing. Ask each builder for:
- A price breakdown by stage or trade: site works, slab, frame, roof, windows, services, linings, wet areas, kitchen, finishes.
- A list of exclusions. Everything they haven't priced.
- A list of qualifications. Any assumption the price depends on, such as "subject to soil test" or "assumes no rock".
- The construction period in days, and how many rain days it allows.
- How long the price is valid.
- Their margin on variations and on PC item and provisional sum overruns.
A builder who won't give you a breakdown is making it hard to check their price. That's worth noting.
Step 3: line up the allowances
This is where most of the difference hides. Prime cost (PC) items and provisional sums (PS) are allowances, not fixed prices. If the real cost comes in higher, you pay the difference plus the builder's margin.
To compare builder quotes fairly:
- List every PC item and PS from each quote, side by side.
- Adjust them to the same figure. If Builder A allows $40/m² for tiles and Builder B allows $70/m², add the difference to A's price.
- Check each allowance against real prices for what you actually want.
- Add up the total of allowances in each quote. The bigger that number, the less "fixed" the fixed price really is.
More on how these work in What is a provisional sum and why you need to know about it.
Step 4: price the exclusions
Go through each builder's exclusions and put your own estimate against every one. Common ones on Queensland quotes:
- Driveway, paths and landscaping.
- Fencing and letterbox.
- Window coverings and flooring upgrades.
- Rock excavation or extra piering.
- Retaining walls.
- Service connections beyond a set distance.
Add each estimate to that builder's price. Now you've got a "levelled" price for each quote. It's common for the cheapest quote to lose most of its lead at this step. My guide to estimating construction costs helps you put realistic figures against the gaps.
Step 5: compare the terms, not just the price
Two quotes at the same levelled price can still carry very different risk. Put these in their own row:
- Build time. A longer build means more rent and loan interest. Put a dollar figure on it if you can.
- Escalation or rise-and-fall clauses. These let the price move after you sign. Get advice before accepting one.
- The deposit. In Queensland, a builder can't ask for more than 5% on a contract over $20,000, except in limited off-site cases.
- The payment schedule. Early stages shouldn't be worth more than the work done at that stage.
- Home warranty insurance. For work over $3,300, the premium must be included. Check it is.
- Licence. Check each builder's licence on the QBCC register.
Put it all in one table. Rows for the quoted price, exclusions added, allowances adjusted, the levelled price, build time and the risks you can't put a price on. Columns for each builder.
Then look down the breakdown column by column. If one builder's frame price is half the others, ask why. It's often a mistake or a missing item, and it's better found now than as a variation later.
Our C4 Asking the Right Questions checklist gives you the questions to put to each builder as you compare. It's on the Checklists page.
Red flags when you compare builder quotes
- A price far below the others. Something's missing, misread or underpriced. It usually comes back as variations or disputes.
- Lots of the builder's own PC items and provisional sums. Fixed work has been turned into estimates.
- Heavy qualifications. "Subject to" on soil, engineering, approvals or "market conditions".
- A very short validity period. Pressure to sign before you've compared properly.
- No breakdown, or one that doesn't add up.
- A deposit above the legal limit. Walk away.
In 26 years in residential construction, I've rarely seen a quote that was much cheaper because the builder was much more efficient. It's usually cheaper because less is in it.
Talking to your preferred builder
Once you've levelled the quotes, pick your preferred builder and sit down with them. Walk through your table. Ask what it would cost to remove each exclusion, whether any allowance looks light to them, and who will supervise your job. The choosing your builder Q&A has more questions worth asking.
Don't shop one builder's price to another. Ask for savings options instead, and check each one against your priorities.
Before you sign, have the contract reviewed. A quote is not a contract, and the contract decides what you're actually getting, so check your own contract and get legal advice.
The short version
Give every builder the same brief, ask for a breakdown, line up the allowances and price every exclusion. Then compare build time, deposit, payment schedule and risky clauses alongside the levelled price. When you compare builder quotes this way, the cheapest price often turns out not to be the cheapest build.
Compare the same house, not three different ones.
FAQs
How many builder quotes should I get?
Three is a good number for a new home. Fewer gives you little to compare; many more wastes your time and the builders'.
Why are builder quotes so different for the same plans?
Usually different allowances, exclusions, site assumptions and margins. Levelling the quotes line by line shows you where the gap really is.
Should I just take the cheapest quote?
Not until you've levelled it. Once exclusions and low allowances are added back, the cheapest quote is often no longer the cheapest.
What's a reasonable margin on PC item overruns?
As a guide, not a rule, about 10% is typical. Whatever it is, it should be written in the contract.
