What is iXBRL Tagging for Accountants in the UK

Team Nomi

Nov 07, 2025
6 minutes read

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If you are an accountant or own a business based in the UK, you may have heard about iXBRL tagging, but what is it all about? It’s actually a way of putting special labels on the words and numbers in your financial reports. These labels assist computers in better understanding the report, but they still make it easy for people to read. 

Because HMRC requires submission of accounts in iXBRL format by the vast majority of companies, it is important to know and understand iXBRL tagging. Using iXBRL tagging software is a simple way to improve your efficiency greater quickly and with less stress. 

What is iXBRL Tagging?

iXBRL (Inline eXtensible Business Reporting Language) tagging is the process of placing specialised coded labels, or “tags,” on financial data in business reports. These labels can be read by machines, but still allow humans to read the original report.

Tagging financial reporting helps HMRC, investors, and financial analysts extract financial information from accounts or reports quickly and without erroneous delays. Think of it as adding metadata to each relevant number or statement in your accounts.​

Why is iXBRL Tagging Important?

In the UK, most companies are required by law to submit their accounts and Corporation Tax returns with their financial statements tagged with iXBRL.

Since 2010, HMRC has mandated that such accounts filed as part of tax returns be done in the iXBRL format, to:

• • Make data easier for systematic processing and analysis
  • Reduce the risks of manual data errors and manual review
  • Accelerate HMRC checking and approvals of tax returns
  • Aid regulators and investors in transparency
  • Allow early detection of fraud or inconsistencies

Not filing tagged accounts can result in financial penalties. As a result, UK accountants must be able to understand and use iXBRL for filings to ensure proper filings and reduce the risk of non-compliance.

How Does iXBRL Tagging Work?

The iXBRL tagging process consists of applying unique labels to every piece of financial information contained in your accounts. These labels, such as those associated with revenue, expenses or assets, are referred to as tags and use a system of rules called a taxonomy. Taxonomy is essentially a structured dictionary that tells one the meaning of the tag.

Accountants can manually tag the accounts by associating each item with the appropriate tag, or they can utilise software to assist with tagging. The iXBRL file produced has been validated, and the labels have been reviewed before sending this report to HMRC, ensuring that all tagging is accurate and follows HMRC’s rules.

Role of iXBRL Tagging Software

Tagging the financial statements yourself is complicated and time-consuming.

• • iXBRL tagging software can automate the tagging process.
  • The software reads your accounts and offers suggested tags from the UK taxonomy.
  • The software has an easy-to-use interface to review and change tags.
  • It also validates the iXBRL output to ensure compliance with all HMRC requirements.
  • Software can help accountants, providing timely and accurate information when reporting to HMRC, compliantly, avoiding penalties, and making a smooth submission.
  • With software, you will minimise human error and simplify your filing process.

Software can help accountants provide timely and accurate information when reporting to HMRC, avoiding penalties, and making a smooth submission.

Benefits of iXBRL Tagging Software

• • Increased Accuracy: Automated iXBRL tagging lessens human error and ensures financial statements are more trustworthy.
  • Consistency: Tagging of all financial data is consistent, enabling stakeholders to easily compare reports at a point in time or across companies.
  • Greater Transparency: Financial data that can be read by machines is easier to extract and compare, creating more understandable financial statements.
  • Internal processes: iXBRL tagging can assist organisations in operationalising both reporting and data management processes within departments.
  • Integration with Cloud Accounting Tools: Several iXBRL tagging applications integrate with cloud accounting platforms, automating workflows.
  • Risk Reduction: Automated tagging lessens the likelihood of incurring costly mistakes and more accurately meets legal expectations.

These advantages support quicker, more secure, and quality financial reporting conforming to UK criteria.

Which Businesses Must Use iXBRL Tagging?

Companies must file accounts in iXBRL format if they prepare accounts under these laws:

• • 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) Regulations 2008

Overseas companies residing in the UK will be required to file accounts in iXBRL.

• • Foreign companies that conduct business in the UK through a permanent establishment (branch, agency) will file country-specific accounts in iXBRL.
  • Foreign companies that submit UK Corporation Tax returns will file accounts in iXBRL if HMRC-recognised accounting standards are used to prepare the accounts.
  • If the company prepares accounts in an accounting standard that HMRC does not accept for Corporation Tax purposes, the company won’t need to file in iXBRL, but will need to file a PDF instead.

How to Get Started with iXBRL Tagging

1. 1. Prepare your accounts as usual.
   2. Export to a compatible format (Word, Excel, etc.).
   3. Apply iXBRL tags using specialist software.
   4. Review and verify the tagging accuracy.
   5. Submit the tagged reports with your tax return to HMRC.

Conclusion

The tagging of financial reporting in iXBRL format makes it more human and machine-readable. Compliance with UK tax laws requires the use of iXBRL tagging. Moreover, it promotes accuracy and transparency, while accountants need the accuracy and efficiency of iXBRL tagging software to produce reports that meet the expectations of HMRC.

If you are looking to use iXBRL tagging, Nomi automatically applies iXBRL tags to your financial data, making it easier to meet Corporation Tax filing requirements quickly and accurately, saving you time and reducing errors.

Frequently Asked Questions

1. 1. What is the purpose of iXBRL tagging?
      iXBRL tagging adds special labels to financial data. These tags make reports readable by both people and computers. This helps HMRC quickly process returns, spot trends, and reduce errors. ​
   2. Why are tags so important?
      Tags provide a standard meaning to each number or item in accounts. This prevents confusion and makes data comparable across companies. 
   3. What is the difference between iXBRL and XBRL?
      XBRL is a language for tagging business data for computer reading. iXBRL is a version of XBRL that keeps the report readable for humans, embedding tags invisibly inside the document. So iXBRL reports look like normal accounts but are machine-readable.​
   4. How do accountants use XBRL?
      Accountants use iXBRL tagging software to add proper tags in reports or let automated software tag the data. They review and validate tags for correctness before submitting to HMRC.​
   5. Is iXBRL tagging mandatory?
      Yes, most companies in the UK must file accounts and tax returns in iXBRL format, according to UK tax laws. Non-compliance can result in penalties. Some specific organisations, like charities, have exceptions based on rules.​
   6. Who has to file iXBRL accounts?
      Companies required to prepare accounts under UK legislation, such as the Companies Act 2006 and related acts, must file in iXBRL. This includes overseas companies with a UK presence. Non-resident companies must also file in iXBRL if using supported accounting standards; otherwise, PDF submission is accepted.