R&D Tax Credit Calculator
Estimate the value of a UK Research and Development tax relief claim under the merged R&D expenditure credit scheme or enhanced R&D intensive support. This calculator is built for accounting periods beginning on or after 1 April 2024, where the modern merged scheme and ERIS rules apply.
Estimate R&D relief value
Enter qualifying expenditure after you have checked that the project and costs meet HMRC rules.
This page supports periods beginning on or after 1 April 2024.
Eligible revenue-type costs only, after apportionment.
Used for the ERIS R&D intensity test.
Use a minus sign for a loss, before the ERIS 86% deduction.
PAYE cap is GBP 20,000 plus 300% of relevant PAYE/NIC.
Merged scheme
20%
Headline taxable expenditure credit for periods beginning on or after 1 April 2024.
ERIS credit
14.5%
Payable credit rate on the surrenderable amount for eligible loss-making R&D intensive SMEs.
Intensity test
30%
Relevant R&D spend divided by total relevant expenditure, including connected-company rules.
Start with the scheme boundary, not the headline percentage
R&D tax relief used to be described in a very SME-versus-large-company way. For current claims that is no longer enough. GOV.UK says the merged scheme and ERIS replace the old SME and RDEC schemes for accounting periods beginning on or after 1 April 2024. The merged scheme gives a taxable expenditure credit. ERIS keeps an SME-style payable-credit route, but only for loss-making SMEs that meet the R&D intensity condition or the one-year grace route.
That is why this calculator asks about the accounting period start date, company size, trading profit or loss, total relevant expenditure and PAYE/NIC. A simple "qualifying spend times 20%" estimate is only the beginning. The useful question is what may be received after Corporation Tax, PAYE cap restrictions and the claim route are considered.
| Route | Best fit |
|---|---|
| Merged scheme | Most eligible companies with periods beginning on or after 1 April 2024. |
| ERIS | Loss-making R&D intensive SMEs that meet the 30% test or grace rule. |
| Old SME/RDEC | Periods beginning before 1 April 2024, not calculated on this page. |
| PAYE cap | Can restrict the amount received unless an exemption applies. |
How this R&D tax credit calculator works
Inputs used
- Claim route: auto, merged scheme, or ERIS.
- Accounting period start and end date, because this page supports periods beginning on or after 1 April 2024.
- Qualifying R&D expenditure and total relevant expenditure for the ERIS R&D intensity test.
- Trading profit or loss before the ERIS additional deduction, Corporation Tax rate and relevant PAYE/NIC.
Calculation method
- Check whether the accounting period begins on or after 1 April 2024.
- Calculate the R&D intensity percentage as qualifying R&D expenditure divided by total relevant expenditure.
- For the merged scheme, calculate the gross expenditure credit at 20% and estimate net benefit after Corporation Tax on that credit.
- For ERIS, calculate the 86% additional deduction, the 186% enhanced expenditure, the adjusted trading loss after the additional deduction and the 14.5% payable credit on the surrenderable amount.
- Apply the PAYE cap unless the company is marked as exempt.
Assumptions
- The qualifying expenditure entered has already been checked against HMRC project and cost rules.
- The Corporation Tax rate selected is used as an estimate of tax on the merged-scheme expenditure credit.
- ERIS is only treated as available where the company is an SME, loss-making before the 86% additional deduction and R&D intensive or covered by the grace option.
- PAYE cap treatment is simplified to the published GBP 20,000 plus 300% of relevant PAYE/NIC formula.
What this does not cover
- It does not decide whether your project qualifies as R&D. Check GOV.UK R&D eligibility guidance and keep a technical narrative.
- It does not calculate old SME/RDEC claims for accounting periods beginning before 1 April 2024.
- It does not apply all CT600L ordering rules, group company PAYE cap detail, Northern Ireland ERIS opt-out rules, grants, subsidised expenditure, subcontracting entitlement, overseas cost restrictions or connected-party adjustments.
- It does not replace a Corporation Tax computation. Use the Corporation Tax Calculator for general CT estimates and get specialist R&D advice before filing.
Worked example: merged scheme
Suppose a trading company has GBP 100,000 of qualifying R&D expenditure in a period beginning after 1 April 2024. Under the merged scheme, the gross expenditure credit is 20%, so the headline credit is GBP 20,000.
The merged credit is taxable. If the company uses a 25% Corporation Tax rate for the estimate, tax on the credit is GBP 5,000, leaving a net benefit of about GBP 15,000 before PAYE cap and CT600L ordering details. A small-profits company at 19% would have a different net result.
This is why the result panel separates "gross credit" from "net benefit". The gross credit is useful for the return. The net benefit is closer to the cash-flow or tax-saving figure a founder usually has in mind.
ERIS is narrower but can be valuable
ERIS is for loss-making R&D intensive SMEs. GOV.UK says the company deducts an extra 86% of qualifying costs, works out the enhanced expenditure at 186%, then can surrender the lower of enhanced expenditure and the adjusted trading loss after the additional deduction.
The payable credit is 14.5% of the surrendered amount, subject to the PAYE cap unless exempt. A company with a small loss may not be able to surrender the full enhanced expenditure; a company with a large loss and enough PAYE/NIC may get closer to the full ERIS cash-credit estimate.
The 30% intensity test is not just this company in isolation if connected companies are involved. HMRC manual guidance says relevant R&D expenditure and total relevant expenditure can include connected companies worldwide.
Claim readiness checks before you rely on the number
Project test first
The project must seek an advance in science or technology and resolve scientific or technological uncertainty. Commercial novelty alone is not enough.
Additional information form
GOV.UK says the additional information form must be submitted before, or on the same day as, the Company Tax Return claim.
Claim notification
First-time claimants, or companies whose last claim is outside the HMRC window, may need to notify HMRC within six months of the period of account end.
PAYE cap evidence
Keep PAYE and NIC support, especially where a cash credit is expected and the claim could be restricted by the cap.
R&D tax credit FAQs
What is the merged R&D scheme?
What is ERIS?
Is the merged scheme credit taxable?
What costs qualify?
Does this calculate my final CT600L boxes?
Official sources
Last verified: May 9 2026. Calculations are estimates based on the published rules and assumptions shown on this page.
- GOV.UK merged R&D expenditure credit and ERIS guidance - merged scheme, ERIS, 20% expenditure credit, PAYE cap and 30% R&D intensity condition
- GOV.UK work out your R&D tax relief - calculation steps for merged scheme and ERIS, including 86% additional deduction and 14.5% payable credit
- GOV.UK check if you can claim R&D tax relief - company eligibility and R&D project definition: science or technology advance and uncertainty
- GOV.UK R&D tax relief collection - claim process steps, qualifying-cost guidance, additional information and CT600 claim route
- GOV.UK check what R&D costs you can claim - staff, externally provided workers, consumables, software, data, cloud and subcontracted R&D cost categories
- GOV.UK claim notification guidance - when a company must notify HMRC within the claim notification period
- GOV.UK additional information form guidance - mandatory additional information form before or on the same day as the Company Tax Return
- GOV.UK Corporation Tax rates - main rate, small profits rate and marginal relief context for net benefit estimates