Inline eXtensible Business Reporting Language — a format where company accounts remain human-readable but carry embedded machine-readable tags, so regulators' systems can process them automatically.

Does iXBRL change what goes in my accounts?

No — it's a file format, not an accounting rule. The content of your accounts is set by the accounts regulations.

Guides

What Is iXBRL? A Plain-English Guide

Q: Where is iXBRL required?

HMRC requires iXBRL computations (and for most companies, iXBRL accounts) with an online Company Tax Return today. Companies House requires all accounts to be filed by software in iXBRL from 1 April 2028.

Q: Do I have to tag my accounts myself?

Almost certainly not — accounts-production and tax software applies the tags automatically.

Updated 10 Jun 2026

iXBRL (Inline eXtensible Business Reporting Language) is a file format that makes company accounts readable by both people and computers — a normal-looking set of accounts with machine-readable tags embedded behind each figure. HMRC already requires it when you file your Company Tax Return online, and from April 2028 Companies House will require all accounts to be filed in iXBRL by software. The practical takeaway: your software does the tagging, not you.

What does iXBRL actually do?

Each number and disclosure in the accounts carries an invisible tag identifying what it is — turnover, balance sheet total, director's name — so a regulator's systems can read the accounts automatically while a human reads the same document normally. One document, two audiences.

Where is iXBRL required today?

HMRC. When a Company Tax Return is filed online, the Corporation Tax computations must be in iXBRL, and for most companies the accounts forming part of the return must be too (a limited set of exceptions can attach accounts as PDF instead). This has been the position for years — if your CT600 has been filed by software or by an accountant, your accounts have been going in as iXBRL already.

Companies House — from 1 April 2028. Under the Economic Crime and Corporate Transparency Act, all accounts must be filed using commercial software in iXBRL format. WebFiling and paper filing close for accounts (other filings, like the confirmation statement, are unaffected). That's the same April 2028 package that adds the mandatory P&L for small companies and removes abridged accounts.

Do you have to tag anything yourself?

Almost certainly not. Accounts-production and tax software applies the tags automatically — "most companies will not have to take special steps" is GOV.UK's own framing. The change to plan for isn't learning a format; it's making sure you (or your accountant) have a software route for Companies House accounts before April 2028, especially if you currently file by WebFiling or paper.

Frequently asked questions

Is iXBRL the same as XBRL? iXBRL is the "inline" version — the tags live inside a human-readable document instead of a separate data file. It's the form used for UK company reporting.

Do I need special software? You need accounts/tax software that produces iXBRL — which all the mainstream packages do. If an accountant files for you, this is already handled.

Does iXBRL change what's in my accounts? No — it changes the file format, not the content. What you must include in accounts is set by the accounts rules (see company accounts), not by iXBRL.

What happens to WebFiling? It stays open for accounts until April 2028, then closes for accounts only. Non-accounts filings such as the confirmation statement continue as now.

I'm a sole trader — does this apply to me? No. iXBRL is a company-filing format — sole traders file Self Assessment instead. See sole trader accounts.

Want your filings in the right format without ever thinking about tagging? See how we help →