Calculators and tools
Six tools, built because we needed them ourselves, using the rates and rules for accounting periods beginning on or after 1 April 2024. Each is free, runs entirely in your browser, and gives an illustration rather than advice: real positions turn on details a calculator cannot see. Our guides cover the same ground in depth, starting with which scheme applies.
If you are not sure where to start, start with the eligibility checker. Everything else on this page assumes the work qualifies, and that is the assumption worth testing first.
R&D eligibility checker
Is our work likely to qualify at all?
Seven short questions on the tests that decide most claims: what you were aiming at, what was genuinely unknown, who can explain it and who commissioned it. It tells you plainly when the answer is no.
What it checks
- Who is claiming
- What you were aiming at
- What was unknown
- Your expert
- Who owns the work
- Claim history
- Tax position
Claim notification deadline checker
Do we have to tell HMRC before we can claim?
Enter your period of account and claim history. It gives you the notification deadline, whether the window is still open, and whether the rule catches you at all. A claim made after the deadline without a notification is invalid however good it is.
Year to 31 Mar 2026 → notify by 30 Sep 2026 →R&D deadline calculator
When does every date in our claim fall?
Enter your accounting dates. It returns every deadline the period produces: filing, claim, notification, the Additional Information Form, enquiry and discovery, each with the rule behind it.
Year to 31 Dec 2025 → claim by 31 Dec 2027 →Claim value calculator
What would a claim actually be worth?
Enter your qualifying spend and profit position. It shows the after-tax value under the merged scheme, or ERIS if you are a loss-making, R&D-intensive SME.
£100,000 qualifying spend → up to £26,970 →ERIS intensity calculator
Do we clear the 30% intensity threshold?
Enter your relevant R&D spend and total relevant expenditure. It gives your intensity ratio and how much headroom, or shortfall, you have against the threshold.
£450k R&D of £1.4m total relevant expenditure → 32.1% →Contracted-out R&D checker
Which of us claims, us or our customer?
Ten questions at most on the statutory test: whether there is a contract, what was done under it, and what the customer intended or contemplated when it signed. It names the section behind every branch and stops where only the contract can go further.
Ten questions → the side the claim sits on, and why →The order a company would use them in
The cards are in that order for a reason. In a claim year the questions arrive in sequence, and each one can close the next.
Does the work qualify at all?
Run the eligibility checker. If the answer is no, nothing below it matters.
R&D eligibility checkerDo we have to notify, and by when?
Run the notification checker next, not last.
Claim notification deadline checkerWhat else is due, and when?
The deadline calculator gives the rest of the timetable from the same period of account. It uses the same notification logic as the checker, so the two cannot give you different dates.
R&D deadline calculatorWhat is the claim worth?
The value calculator, once the first three have settled that there is a claim to value.
Claim value calculatorWhich scheme are we in?
For a loss-making SME, the intensity calculator. A profitable company is in the merged scheme and does not need it.
ERIS intensity calculator
The notification window opens on the first day of the period of account and closes on the last day of the six months beginning with the day after the period of account ends. A claim made after the deadline without a notification is invalid, even where the two-year claim window is still open. The notification deadline is the only one in the regime with no late route and no appeal, and it is routinely missed by companies that had a perfectly good claim.
What each tool decides, and for whom
The six tools answer six different questions, and only one of them is about money.
The eligibility checker decides whether the work is the kind of thing the relief is for. Seven questions at most, on the tests that settle most claims: what you were aiming at, what was genuinely unknown at the outset, who can speak to it in the language of the field, and who commissioned it. It is for a company that has never claimed, or one whose adviser has raised the question and wants a second read before spending money on it. It says no when the answer is no, which is the output most first-time claimants actually need.
The claim notification checker decides whether HMRC has to hear from you before you can claim at all, and by when. It is for first-time claimants, for companies coming back after a gap, and for the accountant who has just picked up a client with an R&D history nobody has written down. Its answer can end a claim outright, as the deadline calculator's claim-window row can for a period that has already closed.
The deadline calculator sets out every date one period of account produces: the filing date, the two-year claim window, the notification deadline, the Additional Information Form sequence, HMRC's enquiry window and the discovery long-stops. It is for anyone holding a period they are not certain is still open, and for advisers who want the dates and the rule behind each one side by side.
The claim value calculator turns a qualifying expenditure figure into an after-tax number under the merged scheme or Enhanced R&D Intensive Support. It is for budgeting and for board papers. It is not for a claim.
The ERIS intensity calculator tests one ratio: whether relevant R&D expenditure is at least 30% of total relevant expenditure, aggregating connected companies on both sides. It is for loss-making SMEs deciding which of the two current schemes they are in, and for groups whose intra-group recharges are quietly distorting the answer.
The contracted-out checker decides which side of a development contract holds the claim on work one company does for another. It applies the statutory test on its own terms, asks the question about the two parties’ accounting periods that decides a contract crossing the 2024 changeover, and weighs the old-scheme factors HMRC weighs without scoring them. It is for contractors who have been told the claim is not theirs, for customers who assumed it was, and for anyone sitting in the middle of a chain.
What the tools deliberately do not model
All six apply standard rules to the figures or dates you enter. None of them sees your contracts, your cost records, your group structure or the state of the field when the work began, and each says so in its own disclaimer.
None of them is tax advice, and none should be relied on for a decision or a filing.
Specifically: no tool tests whether a cost qualifies.
The value calculator assumes every pound entered is qualifying expenditure, and applies no cost eligibility test, no 65% restriction on payments to unconnected subcontractors, no contracted-out or overseas rules, and no PAYE and NIC cap.
The intensity calculator tests one ratio and none of the other ERIS conditions.
The deadline calculator works to a period of account of 18 months or less and declines to answer past that, because the ordinary filing and claim rules are left behind and the position needs working through properly.
The notification checker still answers on a longer period, with a warning and the first accounting period's earlier amendment deadline attached. Both state the rules they apply rather than assuming them.
The eligibility checker reaches a first read on your answers, not a review of your claim.
The contracted-out checker reads no contract, and the contract is what the question turns on: it applies the statutory test to the answers you give about your own papers, weighs the old-scheme factors HMRC weighs without scoring them, and stops where only the documents can go further.
How these figures relate to the guides
The tools and the guides are driven from one rate set and one set of dates. Where a tool gives a figure, the guide that derives it explains why, and every result links to it. The deadline calculator goes further and names the primary source behind each date, so the reasoning can be checked rather than taken on trust.
Where a period began before 1 April 2024 it sits under the old SME scheme or old RDEC rather than the merged scheme and ERIS, and these tools do not price it. Our rates by year page sets out what applied when.
What happens to what you type
Nothing you enter reaches us. Every calculation runs in your browser, on this page, and no figure you type is sent anywhere or stored on your device. There is no sign-up and no gate.
Two things are worth knowing. The calculators put the figures you entered on the page's own address, so that a result can be kept or sent, which means a link you copy after running one carries those figures to whoever opens it. And when a tool produces a result we count that somebody finished it: the name of the tool and the page it happened on, nothing else. No identifier, no figures, nothing that could join one visit to the next, and nothing at all if you have turned site measurement off.
Want the real number, not the estimate?
A first conversation costs nothing and commits you to nothing. You will speak to a qualified adviser, not a salesperson.