R&D Tax Credit Calculator

Since accounting periods beginning on or after 1 April 2024, most companies claim R&D relief through a single merged scheme rather than the old separate SME and RDEC rules. The merged scheme gives an above-the-line credit worth 20% of qualifying R&D expenditure. That credit is itself taxable, so the cash benefit you actually keep depends on your Corporation Tax rate, roughly 15% of spend at the 25% main rate and up to about 16.2% at the 19% small-profits rate.

A loss-making company that is also R&D-intensive, meaning qualifying R&D spend is 30% or more of total expenditure, can instead claim under Enhanced R&D Intensive Support (ERIS). ERIS uplifts qualifying spend by 86% and pays out 14.5% of the resulting surrenderable loss as a cash credit, worth up to around 27% of the original spend. Unlike the merged scheme credit, the ERIS payment is not reduced by Corporation Tax, which is why it is significantly more generous for qualifying loss-making SMEs.

Qualifying expenditure covers staff costs, subcontractor and externally provided worker costs (subject to restrictions), consumables, software and some data and cloud computing costs, where the work resolves genuine scientific or technological uncertainty as set out in the DSIT/BIS Guidelines. Every claim must also be supported by an Additional Information Form submitted to HMRC before the CT600L return.

The rules on qualifying activity, subcontractor restrictions, connected-party rules and the intensity test are detailed, and getting them wrong risks an HMRC enquiry. This calculator gives a rough estimate only; a specialist R&D adviser will confirm what actually qualifies and prepare the claim.