Calculator
Construction Loan Calculator
Estimate how your construction loan may be drawn at each build stage, what you may need to contribute, the monthly interest cost during construction, and your repayments once the build is complete.
Progress payment stages
| Stage | Amount | Bank draws | Client pays | FHOG used | Loan drawn to date | Monthly interest |
|---|
Stage percentages are typical for Perth builders and can be adjusted to match your contract. Your builder's fixed price contract specifies the exact amount payable at each stage. Interest shown is monthly, calculated on the cumulative loan balance drawn at that point. Land is drawn at settlement. The FHOG ($10,000 for eligible new builds in WA) is modelled at slab stage and reduces the loan required for the build.
Want these numbers checked? Talk through the result with Rowan before you make a decision.
How construction loan drawdowns work in Perth
Unlike a standard home loan where the full amount settles at once, a construction loan releases funds progressively as your build reaches each milestone. Your lender requires an inspection report and a progress claim invoice from your builder before releasing each payment.
During the build you pay interest only on what has been drawn. Once the final progress payment is made at practical completion, the loan converts to a standard principal and interest repayment. This is why your repayments are lower during the build and increase once the home is complete.
House and land packages
If you are buying a house and land package in Perth, the land component settles first under a separate contract. Your lender approves the combined loan amount upfront, draws the land cost at settlement, then releases the construction funds in stages as the build progresses. The calculator reflects this by separating the land and construction drawdowns.
What to check against your contract
The stage percentages in the calculator default to typical Perth builder splits, but your fixed price building contract will specify the exact amounts. Common WA builder schedules include a builder deposit (usually 5% paid before construction begins and not part of the progress payment stages shown here). Adjust the percentages in the calculator to match your contract for an accurate picture.
For a full guide to how construction finance is structured in Perth, including what lenders look for, how to prepare your application, and how your builder's progress payment schedule works with your finance, see our construction loan Perth guide. To talk through your specific numbers, book a 30 minute finance strategy session.
Frequently asked questions
How does a construction loan drawdown work?
A construction loan releases funds progressively at each build milestone rather than as a lump sum at settlement. The lender draws down from your approved loan at each stage: slab, frame, lock-up, fixing, and practical completion. You pay interest only on what has been drawn at that point, so your interest cost increases as the build progresses.
What is a progress payment on a construction loan?
A progress payment is the amount released from your construction loan at each build stage. Your builder submits a progress claim invoice and your lender orders an inspection before releasing the funds. The payment goes directly to the builder, not to you. The five standard stages in Western Australia are slab, frame, roof cover or lock-up, fixing, and practical completion.
Can I include the First Home Owner Grant in my construction loan calculation?
Yes. The WA First Home Owner Grant of $10,000 is paid at the first construction draw, which is the slab stage. The calculator lets you enter your FHOG amount and models it at slab stage, reducing the loan required for that draw. It does not apply at land settlement.
What happens to my repayments after the build is complete?
Once practical completion is reached and the final progress payment is made, your construction loan converts to a standard principal and interest home loan. Your repayments increase from the interest-only amount you paid during the build to the full P&I repayment on the total loan balance. The calculator shows this final monthly and fortnightly repayment in the results summary.