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File only the remaining CT600

Last updated: 12 October 2026

Short version. File only the remaining CT600 submits only the second CT600 of a long accounting period. It does not file, change or resend your first CT600. Use it only when HMRC already has your first CT600 with the full accounts, and enter figures for the second return's dates only.

Go to the steps and entry details

On this page

Second CT600 onlyAccounts periods over 12 monthsWhere you see it: Company Profile & Period › Filing purpose

What this option does

File only the remaining CT600 submits only the second CT600 of a long accounting period. It does not file, change or resend your first CT600.

  • When your accounts period ends more than 12 months after it starts, even by one day, HMRC needs two Corporation Tax returns. This option files the second return only, for the dates after the first return ends. In the example below that is 31 May 2026 to 31 May 2026. How the dates are split
  • Your first CT600 must already have been submitted to HMRC. This option will not file it for you. To file both returns, choose Standard return instead.
  • No accounts are sent, because they went to HMRC with your first return. HMRC accepts this. Why HMRC accepts a return without accounts
  • Every figure you enter is treated as belonging to the second return's dates only, and the tax is worked out for that short period.

Is this the right option for you?

Use it if all of these are true

  • Your accounts period ends more than 12 months after it starts. For 12 months or less, this option is greyed out.
  • HMRC already has the first CT600, filed with us or with other software.
  • That first return included the full accounts for the whole accounts period, not just the first return's dates.
  • The first return's figures are correct and do not need changing.
  • You have figures for the second return's dates only, not just full-year totals. Working out figures for each return

Do not use it if

Common mistake: entering the whole year's figures

This option taxes your figures as if they were earned in the second return's dates alone. For a return shorter than 12 months, HMRC reduces the £50,000 and £250,000 profit limits in proportion to the number of days. For a one-day return they become about £137 and £685. A full year's profit is then above the upper limit, so the tax is worked out at the 25% main rate.

Full-year figures entered (wrong for this option)

Turnover
£142,350
Staff costs
£54,750
Other charges
£78,475
Profit taxed as one day
£9,125
Tax at 25%
£2,281.25

Figures for 31 May 2026 only (right for this option)

Turnover
£389
Staff costs
£150
Other charges
£214
Profit for the one day
£25
Tax at 19%
£4.75

If you only have full-year figures and neither return has been filed, choose Standard return instead. We split your figures between the two returns by the number of days and prepare both.

More help: GOV.UK: Corporation Tax rates and short periods · Marginal relief explained · How associated companies divide the limits

Why HMRC accepts a second CT600 without accounts

When your accounts cover more than 12 months, HMRC receives two CT600s but only one set of accounts. Those accounts went to HMRC with your first CT600.

HMRC's guidance says that if you are not sending accounts with a return, you explain why in box 90. HMRC provides a specific reason for this situation, and its own manual tells its staff to find the accounts on the other return.

Accounts
Not attached. They are already with HMRC on your first CT600.
Box 90, reason for not attaching accounts
We enter HMRC's reason "Period of account differs from accounting period, accounts with separate return". In the return file this is the code PoA differs from AP-a/cs with sep rtn.
Tax computation
Attached, for the second return’s dates.

The company and all figures on this page are fictional.

This only applies when your first CT600 included the full accounts covering both returns. If it did not, choose a different option. This is about HMRC only. It does not change what Companies House needs.

More help: HMRC Company Tax Return guide: boxes 80, 85 and 90 · HMRC COTAX Manual COM131041: reason for no iXBRL accounts

Worked example

Company
Linden Example Ltd
Accounts period
31 May 2025 to 31 May 2026 (366 days)
First CT600
31 May 2025 to 30 May 2026. Filed with HMRC, full accounts attached
Second CT600
31 May 2026 to 31 May 2026. Not filed yet
Figures for 31 May 2026
Turnover £389, staff costs £150, other charges £214

The company and all figures on this page are fictional.

Before you start

Both return dates
Check them in your HMRC business tax account or on your CT603 notice. Matching your dates to HMRC
Figures for the second return’s dates
How you work them out is for you or your accountant to decide. Time apportionment or actual figures · HMRC CTM01405
Company UTR
Ten digits, on letters from HMRC. Where to find your UTR
Government Gateway details
The user ID and password for your company's HMRC account. Setting up a Government Gateway account

The company and all figures on this page are fictional.

Companies House is separate. This option deals with HMRC only. Companies House still needs your accounts for the full accounts period by its own deadline. If you have not filed them yet, file them separately.

More help: Filing to HMRC, Companies House, or both · Companies House: file your annual accounts

Step by step

  1. Start a new filing

    Dashboard, company card
    Click New filing. If you see Resume filing, click the small arrow beside it and choose Start new filing →
    Confirm the company
    Tick the confirmation box, then click Continue with this company →

  2. Company Profile & Period

    Accounting period
    31 May 2025 to 31 May 2026
    Special tax regimes
    No
    What are you filing?
    HMRC CT600
    Filing purpose
    File only the remaining CT600
    First CT600 ends
    30 May 2026Already filled in. Change it only if HMRC shows a different end date for your first return. When HMRC's dates differ
    Check the dates shown
    First return: 31 May 2025 to 30 May 2026
    Remaining return: 31 May 2026 to 31 May 2026
    Confirmation tick box
    Tick itIt confirms the first return was filed with HMRC with the full accounts, and that the second return’s dates match your HMRC account.
    Trading status
    ActiveThe form starts on Dormant, so make sure you change it. Choose Dormant only if the company had no income or transactions in the second return's dates. Dormant and trading periods
    What the company does
    Trading

    Click Next →.

  3. Financial Data

    The page shows Figures for 31 May 2026 to 31 May 2026 only. Your accounts were already sent to HMRC with your first CT600. They are not attached to this return. There is no balance sheet or employee section on this route.

    Previous year
    Not shownThis route sends no accounts, so there is no Previous year column.
    Turnover
    389Box 145
    Cost of raw materials and consumables
    0
    Staff costs
    150
    Other charges
    214
    Company tax type
    Standard companyCompany tax types and CT600 box 4

    Leave the other lines and the Tax adjustments section empty unless they apply to these dates. Click Next →.

    More help: Amounts that belong to one date

  4. Review & file

    Check the Corporation tax due card. For Linden Example Ltd it shows:

    Corporation tax due
    £4 .75
    On taxable total profits of £25 at 19.0% · small profits · limits applied £136.99 to £684.93
    Optional
    Click Preview your documents (free) to check the return first
    Subscribe
    Click Unlock Filing and complete payment
    Continue
    Click Continue to submission

  5. Filing credentials

    Corporation Tax UTR
    Your 10-digit UTR
    Gateway User ID
    Your Government Gateway user ID
    Gateway Password
    Your Government Gateway password
    Select the director submitting this return
    The director’s name
    Declaration
    Tick it

    Click Submit to HMRC. There is no accounts approval date on this route, because no accounts are sent.

    More help: If HMRC rejects your sign-in details

  6. After you submit

    The filing page lists one HMRC Government Gateway submission, for the second CT600 only, under Gateway submissions. It shows Accepted once HMRC confirms it. HMRC usually replies within a few minutes, but it can take longer.

    The second return has its own Corporation Tax payment deadline. The Review & file page shows the dates.

    More help: Filing statuses explained · Deadlines for two returns · Paying your Corporation Tax · GOV.UK: pay Corporation Tax

Sample outcome

Second CT600 only31 May 2026 to 31 May 2026, sent as a new return. The first CT600 is not sent again.
£4.75Corporation Tax on £25 at 19%
Accounts not attachedAlready sent to HMRC with your first CT600Why HMRC accepts this

Not the right option?

Open the guide for the option that matches your filings.

Standard returnNeither CT600 filed yet. Files both.Correct a return filed elsewhereAmend the first return, or both returns.Which filing option do I need?Compare every option in one table.

Looking for a different field or step? See all filing wizard guides →

Official sources

Whether this route matches your filings is for you to decide, yourself or with your accountant.

Example companies and figures are fictional. Field names match the filing wizard as of 12 October 2026.