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What iXBRL tagging is

iXBRL, inline XBRL, is a format for accounts that reads as an ordinary document and carries tags that software can read, usually hidden from view.

Accountin · Last checked 2 October 2026

Questions

Who needs iXBRL?

HMRC needs the accounts and tax computations sent with an online Company Tax Return in iXBRL. This has applied to returns delivered on or after 1 April 2011 for periods ending after 31 March 2010. PDF or paper accounts are not accepted for most companies. Unincorporated charities, clubs and societies may send PDF accounts, and their computations must still be in iXBRL.

Does Companies House need iXBRL?

From April 2028 every company must file its accounts in iXBRL using commercial software, and Companies House's web and paper filing for accounts will close.

What happened to HMRC's free filing service?

The joint HMRC and Companies House service for filing accounts and the Company Tax Return closed on 31 March 2026. From 1 April 2026 companies need commercial software. See HMRC's accounts and tax return service has closed.

How does Accountin tag the accounts?

Accountin produces the accounts and the corporation tax computation as iXBRL files, tagged as they are built. See preparing company accounts.

Related guides

FRS 105 and FRS 102 Section 1A comparedWho can use FRS 105 micro-entity accounts and FRS 102 Section 1A small company accounts, the size limits from April 2025, and what each must include.Companies House accounts changes in April 2028From April 2028 Companies House will take accounts only from software in iXBRL, small companies must file a profit and loss account, and abridged accounts end.Companies House identity verification for directors and presentersIdentity verification for directors, PSCs and LLP members has applied since 18 November 2025. Checks for people who file start no earlier than November 2027.Accounts filing deadlines and late filing penaltiesCompanies House deadlines for private company and LLP accounts, the late filing penalties from £150 to £1,500, and when they double.

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