Can I add a note or comment to my CT600 return?

Some customers ask whether they can add a free-text note or comment to their CT600 return before it's submitted to HMRC — for example, to explain an unusual figure or give HMRC extra context. This guide explains what's available.

The CT600 return itself has no general comments box

The Company Tax Return (CT600) that TinyTax submits to HMRC is a structured form of numbered boxes — there is no general-purpose free-text "comments" or "notes" field for arbitrary messages to HMRC, either in HMRC's own schema or in TinyTax's filing form.

Where to add context instead

• Accounts notes: if the note relates to a balance sheet figure (e.g. debtors, creditors, fixed assets), TinyTax automatically generates the relevant statutory disclosure notes in your accounts based on the figures you enter — there's no manual free-text field here either, but the auto-generated note usually covers what HMRC and Companies House expect.
• Contacting HMRC directly: if you need to explain something to HMRC that isn't covered by a box on the return or a note in your accounts, the appropriate route is to contact HMRC directly (by phone or through your Corporation Tax online account) after filing, referencing your UTR and accounting period.
• Your own records: if you just want to keep a note for yourself (not for HMRC), keep it in your own records — TinyTax doesn't currently offer a private notes field on a filing.

Common Questions

Will leaving a note out cause a problem with my return?

No. If none of your entries require further explanation via the standard boxes, HMRC does not expect additional commentary — the structured figures are what they process.