R&D tax relief
How long does an HMRC R&D compliance check take?
HMRC publishes one number for this: its checks into R&D claims took 246 days on average to complete in 2023 to 2024, and 269 days the year before. That's about eight months. This page sets out what sits around that number, stage by stage, using HMRC's own figures and the legislation, and is plain about what the average can't tell you about your own check.
The published figure
246 days, from HMRC's own reporting
The figure comes from table 4 of HMRC's approach to R&D tax reliefs, 2023 to 2024, published on 30 October 2024. It's the only place HMRC has published an average duration for R&D checks, and it covers two years. We checked GOV.UK on 24 September 2026 and no later edition had been published. Neither HMRC's latest quarterly performance update (April to June 2026) nor its annual R&D tax credits statistics report how long checks take.
HMRC table 4: compliance checks (excluding cases dealt with by Large Business teams)
| Measure | 2022-23 | 2023-24 |
|---|---|---|
| Claims received | 90,000 | 61,000 |
| Compliance checks | 8,300 | 9,700 |
| Checks as a share of claims (coverage) | 10% | 17% |
| Tax recovered from checks | £288 million | £441 million |
| Average time to complete a check | 269 days | 246 days |
| Checks where an adjustment was required | 71% | 77% |
| Claims processed within 40 days | 75% | 92% |
As published by HMRC, with row labels shortened. HMRC rounds the counts to the nearest 100. Its footnote says the years show the date the check was opened or the dispute resolved, and that because checks run on a rolling basis the numbers won't fully reconcile. The months below are our own conversion (days divided by the average length of a month, 30.44 days).
In months, 246 days is a little over eight and 269 days is just under nine. The average came down by 23 days while the number of checks rose from 8,300 to 9,700, and HMRC said in the same report that it had over 500 people working on R&D compliance, against around 100 in 2020 to 2021 (HMRC, Approach to R&D tax reliefs 2023 to 2024). It doesn't say why the average fell, so we won't guess.
Stage by stage
What sits either side of the average
The 246 days covers the check itself. The table below puts it in order with the windows HMRC and the legislation set around it. Where a stage has no published duration, it says so rather than filling the gap.
| Stage | What the published sources say about timing | Source |
|---|---|---|
| Claim received and risk assessed | HMRC aims to process 85% of claims within 40 days of receipt, and processed 92% within 40 days in 2023 to 2024. "Processing" includes paying the claim, asking for more information, refusing it, or opening a check on a high-risk claim, so a 40-day answer can be the start of a check. | HMRC, 2023 to 2024 |
| Window to open a check | Generally 12 months from the date the claim was submitted, and HMRC says most checks are opened within it. Some are opened after payment, so money in the bank doesn't mean the claim has been accepted. | HMRC, 2023 to 2024 |
| The check itself | 246 days on average in 2023 to 2024, 269 in 2022 to 2023. No median, range or split by scheme or claim size is published. | HMRC table 4 |
| Outcome | 77% of 2023 to 2024 checks needed an adjustment (71% the year before). HMRC says 89% of the checks settled were resolved by agreement with the claimant. No duration is published for this stage separately. | HMRC, 2023 to 2024 |
| Statutory review | Ask in writing within 30 days of the decision letter. In 2023 to 2024 HMRC held 822 R&D review requests, some carried over from the year before, and concluded 251: 214 upheld HMRC's decision, 33 varied it and fewer than 5 cancelled it. No average review time is published. | HMRC, 2023 to 2024 |
| Alternative Dispute Resolution | 153 R&D requests received in 2023 to 2024. Of those concluded, 22 were fully resolved, 12 had the points in dispute clarified, and fewer than 5 each were partly resolved or not resolved. No duration published. | HMRC, 2023 to 2024 |
| Appeal to the tribunal | 30 days from the end of a review to appeal. One R&D case reached a tribunal hearing in 2023 to 2024, and HMRC won it. | HMRC, 2023 to 2024 |
| After the window | HMRC can still raise a discovery assessment if it finds an inaccuracy an officer couldn't reasonably have known about from the information it had. The time limits depend on the behaviour that led to the error. | HMRC, 2023 to 2024 |
For the tribunal stage, our tribunal case tracker records First-tier Tribunal R&D decisions case by case.
Counting forward
Where the average would land for your check
This adds HMRC's two averages to the date your check was opened. It isn't a forecast: nobody outside HMRC can say how long a particular check will take, and the average hides a spread HMRC hasn't published. It's useful for one thing, which is a sense of whether a check is running long compared with the published figure.
Worked example. A check opened on 1 October 2026 would reach 246 days, the 2023 to 2024 average, on 4 June 2027, and 269 days, the 2022 to 2023 average, on 27 June 2027.
What the average leaves out
Why your check could run a lot longer, or a lot shorter
An average of 246 days can sit on top of a wide spread, with some checks closing quickly and others running far longer. HMRC hasn't published the median or any bands, so there's no way to tell from its figures how typical eight months is. A few things are clear from what it has said:
- Large Business cases are left out. Large companies are handled differently, where HMRC reviews every claim and encourages companies to disclose material uncertainties to their Customer Compliance Manager before filing, so nothing on this page tells you how long their checks take.
- The years are the year a check was opened or a dispute resolved, so a check opened late in 2023 to 2024 may still have been running when the report was written.
- The average is for the check. A statutory review, ADR or a tribunal appeal comes on top, and HMRC hasn't published how long those stages take.
- Nothing is split by scheme, sector or claim size, so a small first claim and a large repeat claim are in the same number.
What moves the clock that you control: HMRC's information requests set a date to respond, and a check that is waiting on the company's answer isn't going to close. If a check has gone on well past the average and the company has answered everything, the legislation gives it a lever: it can apply to the tribunal for a direction that HMRC issue a closure notice within a set period, and the tribunal must give one unless HMRC shows reasonable grounds for not closing (Finance Act 1998, Schedule 18, paragraph 33). That's a formal step, worth taking with a tax adviser rather than alone.
Why the timeline matters beyond HMRC
Cash, lenders and the next claim
Eight months is long enough to cross the next year end. If the company was counting on the credit for working capital, or a lender has been asked to advance against it, an open check changes the picture (see R&D advance funding for how an open enquiry generally changes what's on offer rather than ruling it out). And because 77% of checks in 2023 to 2024 ended with an adjustment, it's worth reading the next period's claim with the same questions in mind before it's filed. The enquiry risk score runs a claim against the features HMRC links to wrong claims.
Next step
If a letter has just arrived, start with what happens when an HMRC R&D enquiry opens. If the check has closed with the claim cut or refused, see a rejected or reduced claim, where the 30-day clock is the thing to watch.
Sources
All HMRC figures, the 12-month window, the review and appeal windows and the discovery assessment rule: HMRC's approach to Research and Development tax reliefs 2023 to 2024 (published 30 October 2024), read on GOV.UK on 24 September 2026. Closure direction: Finance Act 1998, Schedule 18, paragraph 33 on legislation.gov.uk, read the same day. Month conversions and the worked example dates are our own arithmetic on HMRC's day figures.
Talk it through
Need another perspective?
Describe where things stand in a sentence or two, and we'll tell you whether it's something we can help with. There's no charge for this.
Thank you. It's with our team now.
A person reads every enquiry and we'll come back to you with what we think the right next step is. No obligation at any point.
What happens next
- A person on our team reads it. A sentence or two is enough to start.
- If we can help, we may introduce you to a provider and tell you who they are.
- No charge and no obligation at any point. You decide whether to go further.
Adam Parker
Founder of Muswell Rose Consulting Ltd, which trades as Established Finance · former Managing Director of Penny, an invoice finance business, working in mortgages, commercial finance and fintech lending since 2010 (career history).
Last reviewed:
Practical questions
Before you get in touch
How long does an HMRC R&D compliance check take on average?
HMRC's own figure is 246 days for 2023 to 2024, down from 269 days in 2022 to 2023. That's roughly eight months, and just under nine the year before. The figures exclude checks handled by HMRC's Large Business teams, and HMRC hasn't published a median or a spread, so a single check can run well past or well short of the average.
How long does HMRC have to open a check into an R&D claim?
HMRC says that generally it has 12 months from the date the claim was submitted, and that most R&D checks are opened within that time. After the window closes it can still issue a discovery assessment if it finds an inaccuracy it couldn't reasonably have spotted earlier, with time limits that depend on the behaviour behind the error.
Can I make HMRC close an R&D enquiry that has dragged on?
The company can apply to the tax tribunal for a direction that HMRC give a closure notice within a specified period (Finance Act 1998, Schedule 18, paragraph 33). The tribunal has to give the direction unless it is satisfied HMRC has reasonable grounds for not closing the enquiry in that period, so it helps a company that has answered everything, not one still owing information.
How often does a check end with the claim changed?
HMRC reports that 77% of the checks in 2023 to 2024 resulted in an adjustment being required, up from 71% the year before. It doesn't say how large the adjustments were, so that figure covers everything from a small correction to a claim reduced to nothing.
What information do I need?
To start, just a description of what’s actually happening in the business. If it progresses, the provider will ask for the usual things: recent accounts, a sense of turnover and trading history, and details of the specific need.