Timeline for filing CT600 alongwith iXBRL accounts and penalty for delay
There are two aspects to be dealt with:
Corporation tax is usually charged for accounting periods for one year, except for the periods when a company starts and ceases, or if there is a change of accounting date. If the accounting periods in excess of 12 months, then more than one tax return will be required as a tax return cannot extend over a period of more than 12 months.
If you've just started your business, you may have two Corporation Tax accounting periods. As a Corporation Tax accounting period can’t be longer than 12 months, it is possible that in the first year of business your company may have to two sets of Company Tax Returns (even though you only need to file one set of accounts at Companies House.)
For example, if your company was incorporated on 10th December 2019, your company tax returns needs to be filed for two accounting periods:
From second financial year onwards only one company tax return will need to be filed. You will receive a ‘notice to deliver’ from HMRC informing you when these payments are due.
The table below sets out the penalty applicable for late filing of corporation tax:
| Late By | Applicable Penalty |
| One day | £100 |
| three months | additional £100 |
| six months | HMRC will calculate the corporation tax due and will add a penalty of 10 percent of the unpaid corporation tax |
| twelve months | additional 10% of the unpaid corporation tax |
Normally 9 months and 1 day after the end of your accounting period earlier than the CT600 filing deadline itself.
12 months after the end of the accounting period it covers.
The tax payment deadline (9 months and 1 day) is earlier than the filing deadline (12 months), so HMRC receives payment ahead of the full return.
Automatic penalties starting at a fixed amount, increasing the longer the return remains outstanding.
Yes HMRC charges interest on Corporation Tax paid after the 9-month-and-1-day deadline.
Yes, from £60, including free amendments if anything needs correcting after submission.