About Corp Tax Calculator
A UK corporation tax calculator built on the published rates, and an independent record of what R&D tax relief firms print about their own fees, quoted from their own pages and dated.
Why this site exists
A company's corporation tax can be worked out exactly from numbers the government publishes, and the arithmetic is short once you know which thresholds apply to you. The cost of getting somebody to claim R&D relief on that same company's behalf cannot be worked out at all, because most of the firms that do it will not print a number. On 2026-09-09 ten UK firms were read at their own pages: three published a fee and seven did not, and three of the seven run a named introducer programme that pays for a client without saying what it pays. This site does the part that can be done in public. It computes the tax from the published rules, and it records what each firm is willing to print about its own price, including the firms that print nothing, because knowing which conversations start from zero is worth as much as the fees themselves.
Who it is for
The director of a UK limited company who has a profit figure and an accounting period and wants the tax number, with the working shown rather than asserted.
The bookkeeper or accountant checking a corporation tax computation where associated companies, a short period or marginal relief make the thresholds move.
A company deciding whether to have an R&D claim made for it, and by whom, that wants to see what the firms charge before it starts a sequence of introductory calls.
What it does not do
- We give no tax advice and state no view on whether any particular project qualifies for relief. We explain the published rules and record published fees; a company's own facts are for a firm that can be engaged and held responsible for them.
- We publish no estimate of a fee. A firm that does not print a price is recorded as printing none, with the date its page was read, and never with a guess or a figure lifted from a review site.
- We do not rank firms by anything except what they publish, and no firm has paid for a place in the record, an ordering within it, or a mention on any page.
- We do not treat an unreadable page as a finding. Where a firm's page could not be read, that is recorded as unread, because not knowing what a firm publishes is different from knowing it publishes nothing.
What is on this site
2 guides, each with its sources on the page , 66 answers to the questions around them , and the comparison.
- Corporation tax services: "Corporation tax services" is a heading rather than a product, and what sits under it varies more between firms than the price does.
- Corporation tax advice: Most corporation tax questions have a published answer, and this site exists partly to say so: the rates, the thresholds, the deadlines and the penalties are all on GOV.UK and none of them needs advice.
Where the figures come from
UK R&D relief and capital allowances fees verified against each firm's own published page on 2026-09-09 by infra/ingest/hubs/corptaxcalculator.co.uk/ingest_firms.py: every quoted figure re-fetched and matched verbatim (hash-pinned); relief coverage evidenced by the firm's live page.
Who answers for it
Joseph Ellul, Publisher of Corp Tax Calculator; the person who runs the fee ingest, reads every correction sent from this site and answers it.
Reach us
Contact for a question about the site, or enquiries@corptaxcalculator.co.uk. The legal terms are on Terms and Privacy.