The short answer
Patent Box is an elective UK Corporation Tax regime that can apply an effective 10% rate to qualifying profits from patented inventions and certain other qualifying IP. The company must hold qualifying rights, undertake qualifying development, identify the relevant IP income and expenses, and apply the R&D fraction; owning a patent alone is not enough.
What is the Patent Box?
The Patent Box is a UK Corporation Tax regime for companies that profit from qualifying patented inventions and certain other qualifying intellectual property rights. A company must elect into it. The calculation gives an effective 10% Corporation Tax rate on qualifying relevant intellectual property profits—not automatically on all turnover, all profit or every product connected with a patent.
The distinction matters. Patent ownership is the starting point; the company must also meet the development test, identify the income generated by the qualifying right, allocate the related expenses and apply the R&D fraction. Profits outside the Patent Box remain taxed at the company’s applicable Corporation Tax rate.
Who can benefit?
A useful first review asks five connected questions. A “yes” to one question does not make the others automatic.
- 01
Is the claimant within Corporation Tax?
The regime is for qualifying companies liable to UK Corporation Tax.
- 02
Does it hold qualifying IP?
The company must own a qualifying right or hold a qualifying exclusive licence.
- 03
Has qualifying development taken place?
The company, or in some cases its group, must have made a significant contribution to creating or developing the invention, a product or a process incorporating it.
- 04
Does the right generate relevant profit?
Identify the income attributable to exploiting the qualifying IP, then the costs and other statutory deductions that relate to it.
- 05
Are the group and nexus conditions met?
Group companies face an active-ownership test, while acquisition costs and connected-party R&D can restrict the profits receiving the benefit.
Which patents and rights qualify?
For the patent route, the company must own or exclusively license a patent granted by the UK Intellectual Property Office, the European Patent Office or one of the recognised national offices listed below. Certain medicinal and botanic innovation rights can also qualify, but they require a separate rights analysis.
A patent registered elsewhere is not brought into the UK Patent Box merely because the invention is sold in the UK. Conversely, once the qualifying-right conditions are met, relevant sales are not necessarily limited to the territory of the patent office: the income analysis depends on the statutory income rules.
What does qualifying development mean?
The development condition is intended to connect the relief with businesses genuinely involved in the innovation. HMRC describes qualifying development as creating, or significantly contributing to the creation of, the patented invention, or carrying out a significant amount of activity to develop the invention, a product incorporating it or a process incorporating it.
Activity that may support the test
- Originating or materially shaping the inventive idea.
- Testing or improving its viability, usefulness or application.
- Developing a product or process that incorporates it.
- Commissioning external research while retaining meaningful creative and technical input.
Activity that is not enough on its own
- Acquiring and marketing an already developed patent.
- Funding all development without a significant contribution.
- Applying for a patent over acquired rights.
- Commercial negotiations, licensing administration or defending the patent.
“Significant” depends on the facts. HMRC says the contribution can be significant because of its cost, time or effort, or because of its value or impact. A group structure also needs care: where a company is part of a group, active ownership and group development rules can affect eligibility.
What income can qualify?
The starting point is relevant IP income within the company’s taxable trading profits. The legislation separates this into five heads; a further notional-royalty route can apply where qualifying IP produces income without falling within those heads.
| Income route | Examples | What to check |
|---|---|---|
| Sales income | A patented product, a product incorporating the patented invention, or qualifying bespoke spare parts. | Whether the product itself meets the statutory patented-item rules; a remote connection to a patent is not enough. |
| Licence fees and royalties | Income from licensing qualifying patent rights to another party. | The rights covered, the company holding them and whether the receipt forms part of trading income. |
| Sale of qualifying rights | Proceeds from disposing of a qualifying patent right. | Which right was sold and how the receipt enters the company’s taxable trade calculation. |
| Infringement damages | Damages relating to infringement of a qualifying right. | The link between the payment and the qualifying right, including the timing conditions. |
| Other compensation | Insurance or other compensation connected with the qualifying right. | Whether it falls within the statutory compensation head rather than excluded or finance income. |
| Notional royalty | Using a patented process in manufacturing or a patented tool in delivering a service. | The process or service income does not automatically qualify in full. The company may need to elect for and calculate an arm’s-length notional royalty. |
Process patents need a different analysis
If a patent covers only a manufacturing method, sales of the unpatented product are not automatically relevant IP income. HMRC’s notional-royalty provisions can instead attribute an appropriate portion of IP-derived trading income to the qualifying process. The method, evidence and transfer-pricing assumptions need to be supportable.
How is the Patent Box benefit calculated?
The full computation is a profit calculation, not a percentage applied to revenue. In broad terms, the company separates relevant IP income into appropriate streams, allocates related expenses, removes routine and marketing returns, applies the R&D fraction to each sub-stream, and then calculates a Patent Box deduction.
- 1
Identify and stream income
Separate relevant IP income from standard income and, where required, divide it into qualifying-IP, product or product-family sub-streams.
- 2
Allocate expenses
Allocate the debits used to calculate taxable trading profit on a just and reasonable basis.
- 3
Remove routine and marketing returns
Apply the statutory routine-return and marketing-asset calculations to isolate residual IP profit.
- 4
Apply the R&D fraction
Restrict each sub-stream to reflect the company’s own and unconnected-party development expenditure.
- 5
Calculate the deduction
Use the resulting relevant IP profits and the applicable Corporation Tax rate to produce the deduction in the tax computation.
A worked Patent Box example
The reference guide illustrated £1 million of IP profit. The same information is rebuilt below as text and data rather than an image. This simplified example assumes the full £1 million is relevant IP profit after the preceding Patent Box steps, the R&D fraction is 1, the applicable Corporation Tax rate is 25%, and there are no other profits, losses or adjustments.
| Relevant IP profit after the Patent Box steps | £1,000,000 |
|---|---|
| R&D fraction | 1.00 |
| Tax without Patent Box at 25% | £250,000 |
| Patent Box deduction | £600,000 |
| Taxable profit after the deduction | £400,000 |
| Corporation Tax at 25% | £100,000 |
| Illustrative reduction | £150,000 |
For accounting periods commencing on or after 1 April 2023, the statutory deduction is RP × (AR − IPR) ÷ AR: RP is relevant IP profits, AR is the company’s applicable rate and IPR is the 10% Patent Box rate. The applicable rate may be the small-profits rate rather than 25%, so the example should not be treated as an estimate for a particular company.
What is the R&D fraction?
The R&D fraction links the Patent Box benefit to the company’s development expenditure for each income sub-stream. It can reduce the relevant IP profit where the company acquired the IP or paid connected parties to carry out R&D.
Simplified nexus formula
1.3 × (own R&D + unconnected-party R&D)÷own + unconnected + connected-party R&D + qualifying IP acquisition costs
The result is capped at 1. Statutory definitions and adjustments apply.
The numerator receives a 30% uplift, subject to the cap. The denominator includes the numerator expenditure plus relevant connected-party subcontracted R&D and acquisition costs. If there is no R&D or acquisition expenditure and the denominator is zero, HMRC says the fraction is treated as zero.
The calculation is cumulative and should be reviewed annually. Companies therefore need records that track R&D expenditure to the qualifying IP and then to the income sub-stream. Expenditure does not have to appear in an R&D tax relief claim before it can be relevant to the Patent Box fraction.
How and when does a company elect?
The company must elect into Patent Box within two years after the end of the accounting period in which the relevant profit and income arose. HMRC says the election can be included in the computations accompanying the Company Tax Return or made separately in writing; there is no prescribed wording or dedicated box on the return.
Information to assemble before calculating
- A schedule of qualifying rights, applications, ownership and exclusive licences.
- Evidence of the company’s or group’s significant development contribution.
- A map from each right to products, processes, licences and income streams.
- A supportable method for allocating income and expenses between streams.
- R&D and acquisition expenditure traced to each relevant sub-stream.
- The accounting periods, applicable tax rate and Patent Box election position.
Patent-pending periods, losses, acquisitions, group arrangements and changes in streaming methodology can add further steps. The first computation should be designed so that the underlying records can be updated consistently in later years.
Can Patent Box and R&D tax relief be used together?
Potentially, yes. R&D tax relief concerns qualifying expenditure on qualifying R&D activities; Patent Box concerns relevant profits from exploiting qualifying IP. A business can meet both sets of conditions, but one does not prove the other.
In particular, R&D expenditure can be relevant to the Patent Box nexus fraction even if it was not included in an R&D tax relief claim. The practical opportunity is to connect technical project records, IP ownership, expenditure and income early, rather than reconstructing that chain after commercialisation.
For help assessing the commercial opportunity and preparing a claim, explore our Patent Box service.
Frequently asked questions
Can we qualify if another company manufactures the product?
Manufacturing the product yourself is not a universal condition. A company receiving licence fees or royalties may have relevant IP income, but it must still hold the qualifying right or exclusive licence, meet the qualifying-development conditions and apply the full profit and R&D-fraction rules. The contract and actual rights matter more than the label given to the arrangement.
Can a company claim where IP is shared within a group?
Group arrangements can qualify, but the claimant must satisfy the applicable holding, development and active-ownership conditions. HMRC expects a group company relying on active ownership to play a significant role in managing substantially all of its qualifying-right portfolio. Intercompany licences and R&D expenditure also affect the analysis.
Can an exclusive licensee use Patent Box?
Yes, where the licence meets the statutory exclusivity conditions and the company meets the other requirements. HMRC’s public guide refers to rights to develop, exploit and defend the invention, exclusivity throughout an entire national territory, and specified enforcement or damages rights. Group licences have modified conditions, so the agreement should be reviewed in context.
Does a patented process make all product or service income eligible?
No. A method patent does not automatically turn the full sale price of an unpatented product or service into relevant IP income. A notional-royalty election and calculation may be the relevant route, limited to income derived from exploiting the qualifying process or tool.
Does holding a patent automatically reduce tax to 10%?
No. The company must elect and satisfy the qualifying-company and development tests. It must then calculate relevant IP profits, including streaming, expenses, routine and marketing returns and the R&D fraction. Only the resulting qualifying profit receives the effective 10% rate.
Check the detail
Sources & scope
United Kingdom. This guide explains the post-1 July 2021 Patent Box regime and the deduction formula for accounting periods commencing on or after 1 April 2023. Earlier periods, patent-pending profits, losses, group reorganisations and specialist medicinal or botanic rights may require different or additional rules.
This is an InnoFund explanation, not official guidance or advice on a particular claim. The facts, relevant law and applicable scheme rules must be considered together.
Sources checked: 5 September 2026. This is separate from expert sign-off.
- HMRC: Use the Patent Box to reduce your Corporation Tax on profits
Eligibility, recognised patent offices, income, election and public overview
- HMRC Patent Box deduction and election
CIRD201020; applicable-rate formula from 1 April 2023
- HMRC: meaning of qualifying company
CIRD210100; holding and group active-ownership conditions
- HMRC: qualifying development
CIRD210190; significant contribution and excluded commercial activity
- HMRC: relevant IP income overview
CIRD220160; five statutory income heads
- HMRC: method and process patents
CIRD220305; product sales and process-patent limits
- HMRC: notional royalties
CIRD220250; IP-derived income from processes, services and tools
- HMRC: streaming calculation
CIRD275200; income, expenses, routine/marketing returns and R&D fraction
- HMRC: tracking and tracing R&D expenditure
CIRD272000; link expenditure, IP and income
- HMRC: R&D fraction overview
CIRD274100; numerator, denominator, uplift and annual review