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Construction loan calculator

Building a home is exciting, right up until you’re asked for a progress payment you didn’t see coming.

Our construction loan calculator maps out your drawdown schedule against your contract price, cash contribution and approved loan, so you know what’s due at each stage of the build.

It’s the tool we run with clients before the first sod is turned, not after.

The build

Changes and upgrades agreed after the contract.

Your funding

First Home Owner Grant, if you qualify. Check your state’s current amount.

The loan

How construction loan drawdowns work

Unlike a standard home loan, a construction loan doesn’t hand over the full amount at settlement. Your lender releases funds in stages as the build progresses, matched to a standard set of milestones used across the building industry, and you’ll typically need to cover your own contribution alongside each release.

How this calculator helps

  • Shows what’s due at each stage, not just the total loan amount.
  • Helps you plan cash flow across the build rather than being caught out mid-project.
  • Accounts for variations and grants alongside your base contract price.
  • Gives you a clear document to bring to your builder and lender conversations.

The five standard build stages

Most residential builds in Australia follow a broadly similar progress-payment structure.

  • Slab stage: site preparation, foundations and the concrete slab, including under-slab plumbing and drainage.
  • Frame stage: the walls, roof trusses and window frames that give the house its shape.
  • Lock-up stage: external walls, windows and doors installed, effectively securing and weatherproofing the build.
  • Fixing stage: internal work such as plasterboard, cabinetry, doors, skirting and fittings like sinks and baths.
  • Completion stage: final touches, painting, flooring, electrical fittings and plumbing, ahead of handover.

Each stage typically triggers a progress payment from your lender, and you may need to contribute your own funds depending on how your loan is structured. We’ll walk you through exactly how that lines up with your contract.

FAQs

How many drawdowns will there be?

Usually one per construction stage and five in total for a standard build, though it can vary with your builder’s contract and lender.

Do I pay interest on the full loan from day one?

No. You typically only pay interest on the funds actually drawn down at each stage, which keeps early repayments lower than on a fully drawn loan.

What happens if my build goes over budget?

You’ll usually need to cover the variation yourself, either from savings or by increasing your approved loan if your lender agrees. Worth flagging early rather than at the final stage.

Can I switch lenders partway through a build?

It’s possible but adds complexity mid-construction. Most people stick with their original construction lender until the build is complete.

How does a grant fit into the drawdown schedule?

Eligible grants are typically applied at a specific stage, often completion, rather than upfront. We’ll factor that into your cash flow plan.

Want us to check your drawdown schedule against your builder's contract?

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