Off-the-Plan Stamp Duty Concessions by State

What this calculator does

Run this scenario in DocketMath using the Stamp Duty calculator.

DocketMath’s stamp-duty calculator helps you estimate Australian state-based stamp duty outcomes for off-the-plan property purchases—where you buy a property before it is completed, typically under a contract that “finishes” later through construction and final settlement.

A key feature for this topic: many Australian states and territories provide stamp duty concessions for eligible off-the-plan purchases. Those concessions can mean:

• reduced duty rates and/or duty offsets
• special rules tied to contract dates, settlement/completion dates, or development milestones
• treatment that depends on whether the transaction is genuinely “off-the-plan” for the state’s legal definitions

Because concession rules vary by jurisdiction and can be technical, this guide is designed to help you model likely outcomes using DocketMath—not to confirm whether you are legally eligible in your specific case.

How the calculator interacts with concessions

In practice, concession estimates usually change your results through one or more of these mechanisms:

• Your duty line changes when a concession applies (for example, reduced rates or an offset).
• Your timing inputs (such as settlement/completion) can affect whether the transaction meets concession conditions.
• Your property type inputs can influence whether the purchase is treated as a qualifying off-the-plan arrangement.
• Your state selection changes the duty scale and the concession framework used by the tool.
• In borderline situations, the tool’s “off-the-plan vs baseline” modelling can significantly change the output—so it’s worth running alternatives.

If you want the best result, treat it as a modelling exercise: enter details that match your contract as closely as possible.

When to use it

Use DocketMath’s stamp-duty tool when off-the-plan concessions might affect your costs, especially if you’re trying to plan or compare options.

It’s particularly useful when:

• You’re comparing purchase options (e.g., off-the-plan vs existing property) within the same state.
• You have multiple settlement timing possibilities and want to see how stamp duty may change.
• Your contract includes milestones (commencement, construction progress, completion) that could affect concession timing.
• You need a budget estimate before financing is finalised.
• You’re reviewing an agreement and want to sanity-check whether the transaction is the kind of scenario where concessions can apply.

States to pay extra attention to

Off-the-plan stamp duty concessions have existed in multiple jurisdictions, but thresholds, definitions, and effective dates differ. The state where the land is located is the starting point for every calculation.

If you’re unsure which jurisdiction applies, use the contract and land title location. On DocketMath, choose the state based on where the land is, not where your solicitor or developer is based.

Step-by-step example

Below is a practical walkthrough showing how your inputs can change the output when off-the-plan concessions are relevant. (All figures are illustrative to demonstrate the workflow.)

Example assumptions (for modelling)

• Jurisdiction: New South Wales (NSW)
• Property: New unit in a development
• Off-the-plan purchase: Yes
• Contract (entry) date: 15 February 2026
• Settlement date: 30 September 2028
• Purchase price (dutiable value base): AUD 750,000
• Concession possibility: You suspect an off-the-plan concession may apply based on the development and construction schedule

Step 1 — Open the calculator and choose the right tool

Go to DocketMath’s stamp duty calculator: /tools/stamp-duty

• Select the state/territory based on land location.
• If the tool offers a category selector, choose the option that best matches an off-the-plan arrangement.

Step 2 — Enter the purchase price and core inputs

Stamp duty calculations are primarily driven by the dutiable value (often based on the purchase price, subject to what the tool assumes).

Input:

• Purchase price: $750,000

If the interface offers additional transaction fields (for example, special considerations or transaction type), use the fields that best match your contract.

Step 3 — Add off-the-plan indicators

Next, enter the contract and timing information the calculator expects, such as:

• Contract date: 15/02/2026
• Settlement date: 30/09/2028
• Property type / development category: new dwelling / development (match the wording closest to your contract)

The tool can then adjust the estimated stamp duty based on how those inputs line up with concession-style conditions.

Step 4 — Review the output and compare scenarios

A good modelling habit is to run two versions side-by-side:

1. Scenario A (off-the-plan concession logic enabled)

   • Use your contract dates and development type as entered.
2. Scenario B (baseline / no concession modelling)

   • Disable any off-the-plan concession option (if available), or model an equivalent “non-concession” path using the tool’s options.

What to look for in the results:

• Estimated duty total (Scenario A vs Scenario B)
• Whether the tool shows a concession/discount line or changes the effective rate
• How sensitive the estimate is to your dates and category selection

Step 5 — Extract a decision-ready summary

After you run the model, capture:

• your estimated duty total (or range, if the tool provides it)
• which inputs changed the estimate the most (commonly timing or category)

Then use those results to plan cash flow and discuss risk with your team.

Common scenarios

Off-the-plan arrangements often have “twists” that change whether concession-style outcomes apply in modelling. Here are common cases and how to handle them in DocketMath.

1) Same development, different unit allocations

You might be choosing between different units in the same project.

How to model:

• Run one calculation per unit using each unit’s purchase price (and any differing consideration the tool asks for).
• Keep the contract/off-the-plan dates consistent.
• Watch for whether any concession logic has threshold effects.

2) Contract signed during a transitional period

Some jurisdictions update or amend concessions on specific dates.

How to model:

• Use the actual contract date (the execution date shown in the contract).
• Use the contract’s settlement date as nominated.
• If you’re uncertain, compare at least:

  • the stated signing date
  • alternative settlement timings you realistically expect

3) Delayed settlement or developer postponement

Off-the-plan concessions can be sensitive to completion timing.

How to model:

• Run:

  • the expected settlement date
  • a worst-case settlement date that you realistically plan for
• Compare the duty outputs and treat the difference as timing risk.

4) “Off-the-plan” but not actually qualifying (borderline)

Marketing can label projects as off-the-plan, but the legal definition for concessions may differ (for example, based on development stage, dwelling status, or documentation).

How to model:

• If the calculator offers an eligibility or category toggle:

  • test the off-the-plan concession category and
  • test the baseline/non-concession path
• Use the gap between scenarios to understand how sensitive the estimate is to the definition.

5) Bundled arrangements (parking, storage, extras)

Some contracts break consideration into components (e.g., parking/storage upgrades) that may be treated differently for duty base assumptions depending on the tools’ modelling.

How to model:

• If DocketMath asks for a single price figure, enter the amount consistent with what the tool expects for its dutiable value base.
• If the tool allows separate line items, enter them consistently with the way your contract breaks down consideration—so you don’t overstate or understate the base.

Quick comparison table (modelling focus)

Tips for accuracy

To get the most reliable estimate from DocketMath, treat your contract as the source of truth for inputs.

Input checklist (quick pre-calc checks)

Use scenario testing (especially for timing)

Because concession conditions can depend on dates, run:

• a base scenario using the contract’s stated settlement date
• a stress scenario using a realistic delay (for example, +6 months)

If the estimate changes sharply, plan for the timing risk in your budgeting.

Keep date formats consistent

Follow the calculator UI formatting. A common error is mixing day/month/year with month/day/year (which can shift you into a different policy window).

Document your assumptions

When you run multiple versions, save the inputs or screenshots so you can explain later:

• what assumptions you made
• how much

Related reading

• Stamp Duty Calculator Australian Capital Territory - Rates, Exemptions & How to Calculate
• First Home Buyer Stamp Duty Australian Capital Territory - Exemptions & Concessions
• First Home Buyer Stamp Duty Northern Territory - Exemptions & Concessions