Go to the XBRL UK website (Opens new window)
Go to the XBRL International website (Opens new window)
XBRL - the basics
2.1 What is XBRL/iXBRL
XBRL involves the application of computer-readable tags to business data. This enables the
data to be processed automatically by software, bringing great gains in efficiency and
providing an opportunity for high quality analysis of business information.
A company’s financial statements, which have been converted into Inline XBRL (iXBRL), may
appear unchanged to a human reader, but they will contain tags, usually hidden to the eye,
which can be accessed and used by software. XBRL can provide an identifying tag for each
individual item of business data. For example, ‘operating profit’ has its own unique tag, as
does ‘current assets’.
The use of XBRL for filing accounts in the UK is not new. Companies House has been
accepting abbreviated and dormant accounts from audit exempt companies in XBRL for a
number of years using a simple, template-driven system. Many hundreds of thousands of
accounts have already been filed in this way.
Many types of software and data systems have been applying computer-readable tags to
financial data for years. However, these have been defined differently for each purpose and
each type of software. Tags in one system were meaningless to another. No generic
processing of the data was possible.
XBRL is different. It is a world-wide standard, developed by an international, non-profit-
making consortium, XBRL International Inc. (XII). XII is made up of many hundred members,
including government agencies, accounting firms, software companies, large and small
corporations, academics and business reporting experts. XII has agreed the basic
specifications which define how XBRL works.
Clearly, different countries use different accounting standards. Reporting under each
standard reflects differing definitions. The XBRL language uses different dictionaries, known
as ‘taxonomies’, to define the specific tags used for each standard. Different dictionaries may
be defined for different purposes and types of reporting. A special taxonomy, the Global
Ledger or GL Taxonomy, is intended to enable the efficient handling of financial and
business information, at a transactional level, contained within an organisation.
In the UK, three main taxonomies will be used for company reporting: UK GAAP for accounts
created by companies reporting under GAAP regulations, UK-IFRS for the accounts of listed
and other companies filing under the International Financial Reporting Standards (IFRS), the
Corporation Tax or ‘CT’ Computational Taxonomy to represent the additional data used in
tax computations and a Detailed Profit and Loss taxonomy to tag detailed profit and loss
statements that may be attached to the accounts or computations.
The XBRL format being used in the UK for company reporting is known as Inline XBRL or
iXBRL. This consists of a human-readable report, which has XBRL tags embedded in it. The
human readable text is effectively HTML - the basic language of the web. The web file
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contains the XBRL tags, but they are usually hidden and are only displayed to human eyes
when required by software - for example during a process to check the tags.
Read about HMRC’s online filing requirement for Company Tax Returns
2.2 How is iXBRL being used in the UK?
The legislation means that most companies must file their Company Tax Returns, including
financial accounts and computations in iXBRL from 1 April 2011, for accounting periods after
31 March 2010.
HMRC introduced Corporation Tax online filing software in November 2009. This enables
some smaller companies with less complex tax affairs, to file their returns in the correct
format. There is also a range of commercial software and services on the market offering
iXBRL conversion/tagging solutions available with more on the way.
On 1 September 2009, HMRC and Companies House issued a statement announcing a
common approach to the online filing of company accounts that would enable both
organisations to receive accounts in iXBRL format. HMRC and Companies House have since
launched a joint filing service for company accounts. The service, introduced in October 2010,
enables most small companies with relatively straightforward financial affairs, to submit their
company accounts online to both organisations using a 'one stop' online facility.
Please note: this guide explains how businesses can convert what they have to file as part
of their Company Tax Return into iXBRL. For some, conversion into iXBRL may be achieved
automatically by final accounts production (FAP) or tax preparation software, or by using the
HMRC software application. However FAP or conversion software users are likely to have to
do some manual tagging to expand on the automatic tagging provided by their software.
More on who can use HMRC’s online filing software
Read about Corporation Tax Online commercial software options
2.3 What are the benefits of iXBRL?
The introduction of XBRL tags enables automated processing of business information by
computer software, cutting out laborious and costly processes of manual re-entry and
comparison. Computers can treat XBRL data ‘intelligently’: They can recognise the
information in a XBRL document, select it, analyse it, store it, exchange it with other
computers and present it automatically in a variety of ways for users. XBRL greatly increases
the speed of handling of financial data, reduces the chance of error and permits automatic
checking of information.
Inline XBRL (iXBRL) offers additional benefits as it presents XBRL data in a human readable
form, either on screen or in printed output. It also enables the author’s branding and layout
to be maintained so that the recipient can view the same document the author created, whilst
the computer can ‘intelligently’ recognise the embedded XBRL tags.
HMRC will benefit from much more effective analysis software, cutting out unnecessary
queries and helping to deliver better automated risk assessment so they can focus resources
on businesses where the compliance risks are greatest. In addition HMRC and Companies
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House will achieve major improvements in the speed and efficiency with which they handle
business data. Both will cut out manual processes and handling of paper.
As iXBRL becomes established, many companies may find that they can benefit from using
XBRL to improve internal processes. XBRL has many potential benefits for businesses. By
upgrading systems to utilise XBRL they can streamline and automate their methods for
collecting, assembling, monitoring and reporting business data across their whole operation.
They should be able to integrate disparate data systems. They can also turn internal
management reporting and external reporting into processes which are fast, efficient and
Companies may want to discuss the exploitation of these benefits with their accountants and
software and system providers. Consumers of financial data, including banks and other
financial institutions, investors and analysts, can receive, find, compare and analyse data
much more rapidly and efficiently if it is in XBRL or iXBRL format.
iXBRL reporting - how it impacts your business
3.1 Basic principles
iXBRL is purely concerned with the introduction of computer-readable XBRL tags into
business reports to enable automated handling of financial data. It should not otherwise
change the nature and content of company business reports. That continues to be
determined by individual companies in the light of accounting principles, company law etc.
Those who read business reports in iXBRL need not be aware of the existence of XBRL tags.
They may see some changes in the way the user interface of such software works, but the
creation of the XBRL tags will be hidden.
This chapter looks at the impact of iXBRL reporting on different types of companies
3.2 Small companies with simple accounts who do not use accounting
HMRC provides its own free Corporation Tax online filing software - a downloadable form
based product - that can be used by most small companies with relatively straightforward
financial affairs to file their Company Tax Returns online. It includes specially formatted
accounts and computations templates which if used will ensure data is submitted in the right
HMRC and Companies House also provide an optional joint filing service that enables small
companies to enter their accounts data once, using the template provided in HMRC's
software, which can then be used to submit full accounts over the Internet to HMRC as part
of the Company Tax Return and also to send these - or an abbreviated version - to
If a company’s financial reports contain data not catered for in the template provided, then
the company won’t be able to use it. However if the company’s circumstances are such that it
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can legitimately use the CT600 (short) it may be able to attach accounts and computations
produced by commercial software.
Companies will need to register to use the HMRC Corporation Tax Online Service to submit
their returns online whatever software they choose to use. An activation code will be posted
out that can take up to seven days to arrive so companies are advised to register early.
Read about how to register and use the HMRC Corporation Tax Online service
3.3 Companies using final accounts production and tax preparation software
Companies should talk to their commercial software provider or supplier to make sure that
the product offered meets their needs and allows them to deliver a fully compliant Company
HMRC publishes a list of software companies who have successfully tested their products
with them and provided evidence that they have either developed software or manage a
service (or both) that can produce one or more elements of a Company Tax Return. Inclusion
in the list does not imply any judgement by HMRC on the general quality of the software; it
simply indicates that the software meets certain basic criteria including producing technically
valid iXBRL output.
Companies and accountants should consider what processes to follow if accounts and tax
computations are produced at different times, possibly by different individuals or firms. Since
both accounts and computations must eventually be filed in iXBRL, it may be sensible to
ensure accounts and computations are produced in iXBRL when first completed, rather than
trying to convert them at a later date. However, it is up to companies and accountants to
determine what processes to follow in the light of their circumstances. As discussed below, it
is the responsibility of companies to ensure they comply with statutory filing requirements.
Read about Corporation Tax Online commercial software options
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3.4 Companies creating accounts or computations through manual processes
Large companies, among others, may create their accounts and other reports using Excel,
Word or similar text-based software. These companies may elect to integrate final accounts
preparation software into their systems and processes. Alternatively they have two options
for converting their data into iXBRL format:
Use conversion software to turn data from Excel or similar programs into iXBRL. This
will involve some manual effort in identifying and applying the correct tags. The
degree of effort and nature of the task will vary depending on the software chosen. A
number of conversion products are available. Some conversion software is listed as
‘recognised’ on the HMRC website and company accountants or others may be able
to offer advice on the merits of suitable software. Software may allow templates to be
created which will enable tagging to be reused for subsequent reports, so that
conversion, once done for an initial report, becomes straightforward in the future. In
some cases, it may be possible to use the same template across a range of
subsidiaries within a group. The basic issues involved in tagging financial reports and
producing iXBRL are described in the next chapter.
Outsource the conversion of reports into iXBRL to an external organisation. These
take accounts prepared in a traditional manner, covert them to iXBRL and add the
More information on those companies offering a managed tagging service
3.5 Company responsibilities for iXBRL filing
It is a company’s responsibility to ensure that it adequately complies with requirements for
filing in iXBRL. Companies which are using final accounts production or tax preparation
software to file in iXBRL should ensure that their software is adequate to handle the type and
scope of data in their reports. They may wish to consult their software providers or
accountants on this point.
Companies using external managed tagging services to produce iXBRL formatted accounts
and/or computations are responsible for ensuring that it can be incorporated with the online
CT600 return form for submission. Companies using conversion software to turn their
accounts and computations data into iXBRL in-house are responsible for ensuring these
comply with HMRC online filing requirements. They may wish to consult their accountants or
auditors on their processes.
HMRC accepts that that during the transition to iXBRL some errors and omissions may occur
with tagging and HMRC are keen to help companies get it right rather than penalise them.
Where companies have made a reasonable attempt to get it right, HMRC will adopt a
sympathetic approach for the first two years
and will be focussing on providing help and
support to correct the errors, rather than rejecting the return.
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Creating reports in iXBRL
4.1 Creating iXBRL reports - introduction
This chapter is aimed at businesses that wish to create reports in iXBRL using conversion
software and partly manual processes.
It outlines the principles, as well as the risks and issues involved at a business level. It is
intended to give a view of the nature of the task involved in conversion. It is not possible to
give an estimate of the effort required, since this will depend on the size and content of a
report and the software and methods chosen.
A separate ‘Preparers and Developers Guide’ provides detailed guidance for those working
on this task.
Go to the XBRL UK preparer and developer guide
(Opens new window)
4.2 Creating iXBRL reports - the basic principles
The conversion of reports in ‘native’ format, such as Word or Excel, into iXBRL
involves matching the data in the accounts and tax computations with XBRL tags from the
appropriate taxonomies using a software tool that presents the marked-up (or 'tagged')
report(s) in an (X)HTML document.
Ideally - and in practice most of the time - such ‘data tagging’ should be straightforward, with
an obvious one-to-one match between financial line items and tags in the report. However,
there will be times when it is not obvious what the most appropriate match is, or that it
becomes clear that no match can be found. This is due to the fact that company accounts
and computations are varied and detailed. The UK taxonomies which define the available
tags have to be large enough to provide tags for most items which typically appear in
financial reports, but they are not exhaustive.
Therefore, although taxonomies and conversion software are designed to make manual
tagging as easy as possible, it will inevitably involve time and effort, especially in the first
After the first year, people will have a better understanding of taxonomies and the tagging
process. As they move forward, the previous year’s tagging will form the basis of the next
year so things will get easier and quicker.
The precise mechanisms of tagging and data entry will depend on the software chosen. For
example, some existing software requires a tag to be dragged from a taxonomy list onto the
appropriate line item in an Excel file. However, other software products may offer different
features, such as the use of prepared templates.
4.3 Presentation of reports in iXBRL
The human readable presentation of reports in iXBRL is entirely in the hands of preparers.
The fact that underlying tags are being added need not influence the presentation which a
company chooses to adopt - layout, style, terminological and branding preferences may all
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Companies should continue to describe line items in accounts in the way they choose. The
description of tags in taxonomies is purely to identify the tag clearly; they are not intended to
determine how a company describes that item. Tag descriptions will not necessarily align
exactly to wording in accounts but the concepts they both represent should match sufficiently
The taxonomies (or dictionaries) used for filing to HMRC and Companies House are:
UK GAAP - this covers the typical content of reports and accounts filed under UK
UK-IFRS - this covers the typical content of reports filed under IFRS in the UK. It
includes a special version suited to banks. It also has special sections for data for a
small number of particular industry sectors, such as oil, mining and gas companies and
CT - Computational Taxonomy contains tags for key items in tax computations
Detailed Profit and Loss Taxonomy contains tags for items that may appear in a
detailed profit and loss statement that has been attached to the Ct computation or
The accounts taxonomies include some common components. These cover standard
business information, such as company name, activities and similar data, and standard
reports such as the Directors’ Report and Auditors’ Report.
The accounts taxonomies are available for download from the XBRL UK website and the CT
taxonomy from the HMRC website, but we expect them normally to be bundled with
conversion software. Taxonomies can only be viewed in suitable software. However, XBRL
UK has provided Excel lists of their content, but these provide limited views of the taxonomy.
Taxonomies like UK GAAP present a list of tags in the same format as a set of typical
accounts, with a profit and loss statement, balance sheet, notes to the accounts etc.
However, because taxonomies have to cover a large range of possible tags, their content is
much larger than that of ordinary single company reports.
The labels on tags are similar to those in ordinary accounts, but tend to be longer and more
explicit in order to identify them clearly. For example, the tag for the tax item in the UK GAAP
taxonomy profit and loss statement is ‘Tax on profit or loss on ordinary activities’, not just
‘Tax’ which is the description which might appear in a set of accounts.
The label and position of a tag in a taxonomy will normally identify it unambiguously, but
taxonomies also provide subsidiary information, such as debit/credit type and accounting
references, which may aid in identification.
Taxonomies inevitably present a ‘common denominator’ view of data. Their structure will not
necessarily match that of an individual company’s accounts or computations. In some cases,
a company may need to use a tag from the taxonomy notes within a primary statement and
The taxonomies only provide tags for data items whose appearance in company reporting is
reasonably typical or predictable. They do not define tags for every eventuality or for
company-specific or unusual line items. Therefore, it is almost inevitable that items will exist
in the financial accounts which will have no XBRL tag. This is acceptable to HMRC since
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these items will still be visible in the human readable web document, which preserves the full
format and details of the accounts.
Taxonomies will be updated from time to time, probably on an annual basis, to reflect
changes in regulations and feedback from users. Announcements on updated versions and
their dates of validity will be published via XBRL websites and other normal channels.
Software providers are expected to update their software where necessary to handle the new
Find detailed information about taxonomies on the XBRL UK website (Opens new window)
More about taxonomies on the HMRC website
4.5 Scope of tagging
The accounts sent with your return need to be in iXBRL format if they are required to be
prepared under any of the following legislation:
Individual accounts required to be prepared under Chapter 4 of Part 15 of the
Companies Act 2006
Building Societies Act 1986
Friendly and Industrial and Provident Societies Act 1968
Friendly Societies Act 1992
Insurance Accounts Directive (Miscellaneous Insurance Undertakings)
In addition - overseas companies resident in the UK must deliver the accounts required by a
notice to deliver a return in iXBRL. Also a company not resident in the UK, but
carrying on a
trade in the UK through a permanent establishment, branch or agency in the UK, must
deliver any trading and profit and loss account and any balance sheet of the UK
establishment, branch or agency required as part of its return in iXBRL format.
In other circumstances, accounts
can be sent as either iXBRL or PDF files.
Accounts often include more than just financial data, for example charts and diagrams
showing trends over a number of years, comparison with sector indices and general
descriptive information on the scope of business and operations etc. Not all of this needs to
be tagged. The following describes how preparers should identify which data within a set of
accounts needs to be tagged:
The starting point is the accounts you are required to send as part of a Company Tax
Return in iXBRL format. For example, a company incorporated under the Companies
Act is required to send the individual accounts they must prepare for their members -
a balance sheet, a profit and loss account and notes to the accounts -including any
Directors’ and Auditor’s reports similarly required.
All instances of data within the balance sheet, profit and loss account and notes to the
accounts must be tagged. If a data item appears more than once then it must be
tagged each time.
The Directors’ report and Auditor’s report must also be tagged, but only to the extent
that data within these are also within the Directors’ report and Auditor’s report sections
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Documents you may be interested
Documents you may be interested