About this site

This is a single-purpose tool. It works out what a UK company can claim in R&D tax relief under the merged RDEC scheme or enhanced R&D intensive support, and it does nothing else.

Why it exists

The April 2024 reform replaced two schemes with two different schemes, and most of the calculators still online were built for the old rules. Worse, a lot of them quote the merged scheme at 20% without mentioning that the credit is taxable, which overstates the benefit by a quarter at the main rate. This tool shows the gross and net figures side by side because the difference is the whole point.

How it is built

Every rate comes from an HMRC or GOV.UK primary source, is listed with that source on the methodology page, and carries the date it was last verified. Rates currently stand as verified on 2026-08-14. The calculation logic is covered by unit tests whose expected values were worked out by hand from the HMRC guidance, not generated from the code itself.

The calculator runs entirely in your browser. Nothing you type is sent anywhere. See the privacy policy.

What this is not

It is not a firm of accountants, it is not affiliated with HM Revenue & Customs, and it is not tax advice. An R&D claim turns on whether your project meets HMRC's definition of R&D and on which of your costs qualify. Those are judgement calls this tool does not make. Before you file, take advice from someone who has looked at your actual books.

How it makes money

Currently it does not. There are no adverts, no affiliate links, no lead forms and no sponsored placements on this site. If that changes, it will be disclosed here first.

Corrections and contact

If a figure is wrong or out of date, send the HMRC source that contradicts it to hello@rdtaxcreditcalculator.co.uk and it will be corrected. Corrections to statutory figures are treated as urgent.