Ordinary annual accounting period
A company wants the return deadline for a standard 12-month accounting period.
The tool returns the date 12 months after the accounting period end.
Practical compliance tool
CT600 Filing Deadline Calculator
Calculate the standard CT600 filing deadline from the accounting period end using the normal 12-month filing rule.
The filing deadline for the return is separate from the Corporation Tax payment date, so this tool keeps the return timing explicit.
CT600 Filing Deadline Calculator
Calculate the standard CT600 filing deadline from the accounting period end using the normal 12-month filing rule.
What the CT600 date means
The result shows the standard filing deadline for the CT600 return once the accounting period end is known.
It helps keep the return filing date separate from the earlier payment deadline that often drives cash planning.
Rule summary
Standard CT600 filing timing
In a standard case, the Company Tax Return is due 12 months after the end of the accounting period.
That deadline is later than the ordinary Corporation Tax payment date, so businesses often need both dates visible at the same time.
Worked examples
How the result behaves in practice
Keeping payment and filing separate
A business already knows the payment deadline but needs to confirm when the return itself must be filed.
The calculator isolates the CT600 date so the return work can be planned properly.
Turn the result into an action plan
Keep the payment deadline and CT600 filing deadline visible together rather than assuming they fall at the same point.
If the filing date has already passed, move straight to the late filing penalty tool.
Add both dates to the company calendar so tax work is tracked as a sequence, not as isolated deadlines.
Read the guide
CT600 filing deadlines
Understand how the standard CT600 filing deadline is set and why it must be tracked separately from the earlier tax payment date.
Assumptions and limits
This tool applies a published rule set directly and is designed for standard scenarios.
Assumptions
- The inputs entered are complete and reflect the facts for the relevant filing, tax, or compliance period.
- The tool is used for a standard scenario rather than a specialist exception, relief, or disputed case.
Limits and rule basis
- This tool does not replace detailed professional review where the facts are unusual or contested.
- If the underlying rule depends on reliefs, appeals, or special handling, the real outcome may differ.