Calculating your Research and Development (R&D) Tax Incentive is about more than just adding up a few receipts at the end of the year.

It requires a precise understanding of which costs are eligible and how the government’s notional deduction system applies to your specific business structure. As of 2026, the Australian Taxation Office (ATO) has implemented stricter rules around cost apportionment, meaning you must be able to prove the connection between every dollar claimed and a registered R&D activity.

In this guide, we break down the math and the categories you need to master to estimate your potential refund.

Determining Your Aggregated Turnover

The first step in any calculation is determining which of the two R&D “streams” your company falls into. This is decided by your aggregated turnover, which is essentially the total income of your business plus any entities that are connected to you or affiliated with you.

  • If your aggregated turnover is less than $20 million, you fall into the Small-to-Medium (SME) category
  • If your aggregated turnover is $20 million or more, you fall into the Large Entity category
  • Aggregated turnover includes global income if you have international parent companies or subsidiaries
  • You must account for the income of any entity that owns more than 40 percent of your company
  • The turnover threshold is checked annually, meaning you could move between streams from one year to the next

This threshold is vital because it determines whether your offset is refundable (cash in hand) or non-refundable (a reduction in tax payable).

The Notional Deduction Minimum

Before you dive into the deep math, your company must meet a minimum spending requirement. For most businesses, the total “notional deductions” must be at least $20,000 for the financial year.

  • This $20,000 can be made up of staff costs, contractors, and consumables combined
  • If your spend is under this amount, you can only claim the incentive if you use a registered Research Service Provider (RSP)
  • Smaller startups should track even minor expenses to ensure they cross this threshold
  • If you fail to meet the $20,000 mark and don’t use an RSP, you cannot access the R&D Tax Incentive for that year

Identifying Your Eligible Staff Costs

For the vast majority of Australian businesses, staff costs represent the lion’s share of an R&D claim. However, you cannot simply claim the total salary of every developer or engineer. You must apportion their time based on their actual involvement in registered R&D activities.

  • You can claim the R&D portion of gross salaries and wages
  • Payroll tax and superannuation contributions are also eligible for the R&D premium
  • Worker’s compensation insurance premiums can be included in your calculations
  • Bonuses and other “on-costs” are generally eligible if they relate to the R&D period
  • You must exclude any government subsidies like training grants from these salary amounts

To calculate this accurately, you need a percentage of time for each employee. If a lead developer earns $150,000 and spent 60 percent of their year solving a technical uncertainty, your eligible staff cost for that person would be $90,000 plus their associated on-costs.

Calculating Contractor and Consultant Expenditure

Many Australian companies rely on external specialists to help them innovate. While these costs are eligible, the rules for contractors are slightly different than for in-house staff.

  • Contractor costs must be for activities that were performed directly for your company
  • You can only claim the portion of the contractor’s work that relates to an eligible R&D activity
  • If a contractor provides a mix of routine maintenance and experimental work, you must split the invoice
  • Expenditure to “associates” (like directors or related companies) must be paid in full by the end of the financial year to be claimed
  • Overseas contractors are only eligible if you have a pre-approved Overseas Finding from AusIndustry

It is important to ensure your contractor invoices are detailed. An invoice that simply says “consulting services” will likely be rejected during an ATO review. Sentinel House recommends asking contractors to itemise their work against your specific R&D project names.

Apportioning Overheads and Indirect Costs

Innovation does not happen in a vacuum. It requires an office, computers, electricity, and administrative support. The R&D Tax Incentive allows you to claim a portion of these “indirect” costs, but the calculation must be fair and reasonable.

  • Rent and lease costs for the area where R&D work is physically performed
  • Electricity and gas costs used to power R&D equipment or laboratories
  • Internet and server costs, particularly important for software companies using cloud environments
  • Maintenance and repair costs for machinery used in experimental trials
  • General administrative support specifically linked to the R&D project

There is no “fixed percentage” that the ATO accepts for overheads. You must use a logical method, such as floor space for rent or headcount for utilities, to justify your figures. This is an area where having a specialist firm like Sentinel House is invaluable, as we can help you defend your apportionment logic if the ATO ever asks for proof.

Calculating the Decline in Value of Assets

If you have purchased expensive equipment or hardware to perform your R&D, you don’t claim the full purchase price in one go. Instead, you claim the “decline in value” (depreciation) for the time the asset was used for R&D.

  • Only the proportion of use dedicated to R&D can be claimed as a notional deduction
  • This applies to lab equipment, specialised manufacturing machines, and even high-performance computers
  • Assets used for both R&D and general business must have their usage logged
  • If you used the Instant Asset Write-Off for a piece of equipment, the R&D rules for that asset change significantly
  • Intangible assets like patents or certain software licences also have specific depreciation rules

The Mathematics of the Offset Rates for 2026

The actual benefit you receive is calculated as a “premium” over the tax you would have otherwise saved via a standard deduction.

  • For SMEs with a 25 percent tax rate, the refundable offset is 43.5 percent
  • This creates a “net benefit” of 18.5 percent (43.5 minus 25)
  • For Large Entities, the calculation is based on “R&D Intensity”
  • Intensity is your R&D spend divided by your total business expenses for the year
  • Spend up to 2 percent intensity receives a premium of 8.5 percent above the tax rate
  • Spend above 2 percent intensity receives a premium of 16.5 percent above the tax rate

For a large company on a 30 percent tax rate, this means their R&D offset would be either 38.5 percent or 46.5 percent depending on how much they are spending relative to their total budget.

Adjustments for Feedstock and Clawbacks

The calculation can become more complex if your R&D project involves production that leads to a saleable product. This is known as the Feedstock Adjustment.

  • If you sell the output of your R&D trials, you must pay back a portion of the tax benefit
  • This prevents companies from getting a subsidy for materials they effectively “sold” for profit
  • Clawback adjustments also apply if you have received other government grants for the same work
  • These adjustments must be calculated precisely to ensure you don’t accidentally over-claim
  • Managing these “add-backs” is one of the most technical parts of an R&D tax return

Calculating your R&D Tax Incentive is a process of turning technical effort into financial data. While the basic categories of staff, contractors, and overheads are the building blocks, the real challenge lies in the detail. Accurate apportionment, meeting the “At Risk” rules, and correctly applying the intensity tiers are what separate a successful claim from a compliance nightmare.

In the 2026 tax environment, the ATO is looking for evidence-backed calculations rather than estimates. This is why many Australian businesses choose to partner with Sentinel House. We don’t just calculate your claim; we build a robust financial framework that justifies every cent. Our approach ensures you maximise your “net benefit” while remaining fully compliant with the latest regulations.

If you are ready to move beyond estimates and secure the funding your innovation deserves, we are here to help.