Why a date decides so much
The reform landed in two stages, not one
ERIS, the more generous route for R&D-intensive loss-making SMEs, applies from accounting periods beginning on or after 1 April 2024. That's the same date as the wider merged scheme, which replaced the old SME/RDEC split for almost everyone else. Periods beginning between 1 April 2023 and 31 March 2024 sit in an older transition window with their own separate provisions, predating ERIS by name. A company with a period straddling any of these dates can be on genuinely different rules from its own previous year. Untangling that is most of what this tool is for.
Check yours
Work out your scheme
Free to use, nothing is saved or sent anywhere. Figures are used only to compute your R&D intensity ratio in your browser.
Your scheme, for this accounting period
Enter your accounting period start date above
Answer whether the company is loss-making to see your result.
This period predates both reforms. Neither ERIS nor the merged scheme existed yet. You're under the old, pre-reform structure: a separate SME scheme (enhanced deduction, with a payable credit if loss-making) and a separate RDEC scheme, generally for large companies and for subsidised or contracted-out R&D under the old rules. Which one applies turns on company size and the shape of the work, questions this tool doesn't check. See R&D claim services or talk it through directly.
Transition window, not ERIS. ERIS, under that name, applies from accounting periods beginning on or after 1 April 2024, so this period predates it. You're under the old SME/RDEC split. HMRC's own manual (CIRD121000) describes a separate, retrospective provision letting R&D-intensive SMEs claim a higher tax credit rate under the old SME scheme for periods in this window, distinct from ERIS in its own mechanics. This is genuinely one of the more tangled corners of the reform. Confirm it directly with an adviser rather than relying on a simplified tool for this specific one-year window, including whether it applies given your loss-making status and R&D intensity.
Merged scheme applies, and you may also qualify for ERIS. Loss-making, with an R&D intensity of %, at or above the 30% threshold for accounting periods beginning on or after 1 April 2024 (CIRD123000). ERIS generally pays a more generous cash credit than the merged scheme for loss-making, R&D-heavy SMEs. Confirm the ratio, including connected companies, and which route is actually worth more in your circumstances, with an adviser.
Merged scheme applies, ERIS likely isn't available. Based on the figures entered, R&D intensity of % is below the 30% threshold for accounting periods beginning on or after 1 April 2024. You claim through the merged scheme, a single RDEC-based credit. If you qualified for ERIS last period and have simply dipped just under the threshold this period, check the one-year grace period before assuming you've lost it (CIRD123000).
Merged scheme is your baseline for this period. Whether the more generous ERIS route is also available depends on R&D intensity against a 30% threshold. Enter approximate figures above for an indication, then confirm the exact ratio, including any connected companies, with an adviser.
Merged scheme applies. A single RDEC-based expenditure credit, for accounting periods beginning on or after 1 April 2024. ERIS isn't relevant here. It's restricted to loss-making companies (see gov.uk, the merged scheme).
This tool routes you to the correct scheme based on period start date, loss-making status and R&D intensity. It doesn't check whether your work qualifies as R&D at all (that's covered on R&D claim services), and it doesn't check claim notification or the Additional Information Form, covered on the notification deadline checker and the Additional Information Form pages. Sources: gov.uk, "Research and Development Tax Relief, The Merged Scheme: R&D Expenditure Credit (RDEC)"; HMRC manual CIRD123000, R&D intensity condition. Not tax advice.
What the intensity figure doesn't include
Connected companies count in HMRC's test
The calculation above is deliberately simple: R&D expenditure divided by total expenditure, as a percentage. HMRC's actual test aggregates qualifying R&D expenditure and total relevant expenditure across any connected companies, not just the claimant on its own. Two companies with identical standalone figures can land on opposite sides of the 30% line depending on group structure. Treat the percentage here as an indication to bring to an adviser, not the final word.
Alternatives and limitations
Knowing your scheme is only the first step
If the result above points to ERIS or the merged scheme and you haven't started preparing a claim, that's covered on R&D claim services. If contracted-out work, overseas costs, or grant funding are part of the picture, those change what counts even once you know your scheme. See contracted-out R&D, overseas R&D costs, and grants and R&D.
