R&D claim time-limit checker

You enter the first and last day of the period of account. The checker works out whether the period is 18 months or shorter, or longer, applies the matching time limit and shows the last date for making or amending a claim, plus the days left or the days since it passed. It runs in your browser and stores nothing.

For a period of account of up to 18 months, two years from the last day of the period of account. For a longer period, 42 months from its first day. The rule is in paragraph 83E of Schedule 18 to the Finance Act 1998. The checker applies whichever of the two tests fits your period.

It is the period for which the company draws up its accounts, which is usually, but not always, 12 months. The time limit is measured from its end, or for longer periods from its start, so the correct dates matter. Use the dates in the filed or draft accounts. Please check it carefully.

The rule gives a fixed overall allowance for longer periods: 42 months from the first day, rather than two years from the last. This is what paragraph 83E provides, and the checker applies whichever test is relevant. For long periods, it is worth confirming the dates with an adviser. Please check carefully.

Yes. Claims and amendments are made through the company tax return, and the same limit applies. The checker therefore shows the last date by which a claim can be made or changed for the period. After that date, HMRC's rules on late claims are narrow. The checker shows one date for both.

An HMRC officer may allow a late claim. We would not rely on it. The rules for allowing a late claim are limited, so assume the date is a hard deadline. If it has passed, speak to us promptly about what, if anything, can be done. The earlier you ask, the more options you may have.

No. The notification deadline, six months after the end of the period of account, applies only in certain cases for periods beginning on or after 1 April 2023. The claim time limit applies to every claim. Missing the first can make a claim invalid, and missing the second means you cannot make or change it.

In paragraph 83E of Schedule 18 to the Finance Act 1998, on legislation.gov.uk. It sets the time limit for claims and amendments made through the company tax return. HMRC's guidance repeats it, and the checker follows the legislation. You can read the paragraph yourself on legislation.gov.uk, and the tool page links to it, so you can check the checker.

Where HMRC removes an SME claim, the company has an extra 30 days to switch to RDEC. The checker mentions the window, but does not calculate it. It matters for older periods, so speak to us if HMRC has removed a claim from a return. The window applies only after such a removal.

Yes, within the time limit, through an amended company tax return. The same date applies as for the original claim. If the amendment adds a new claim for a period that needs notification, the notification deadline may also matter, so check both. Do not leave amendments to the last week.

The first and last day of the period of account, as shown in the accounts. If the company changed its accounting date, or has a long first period, check each period separately. When in doubt, ask your accountant for the dates, or ask us. Accountants can usually supply them in a minute.

Tell us what happened and the dates involved. We will see what is possible. An HMRC officer may allow a late claim, but you should not assume that will happen. If the problem was an adviser's, it is also worth keeping all the correspondence. Keep all emails and dates, as they help us assess the position.

No. It only checks time. Whether a claim is worth making depends on whether the work qualifies and what it would be worth, which our benefit calculator helps to estimate. It is better to check both before the deadline gets close. Use the benefit calculator for a rough idea of value; whether the work qualifies needs an honest look at what was done.

The time limit is the same, so the checker works for older periods. The rules for what you can claim are different, because the older SME and RDEC schemes applied. If you are making a late claim or amendment, speak to us about the scheme rules for that period. Please check the scheme first.

That the dates you enter are right, that the period of account is the relevant period, and that no special rule applies. It is a guide to the general rule and not advice on your position. If the date is close, the safest course is to talk to us early.