Corporation tax (CT600)
The tax UK limited companies pay on their taxable profits — reported annually on the CT600 return to HMRC and paid nine months and one day after the accounting period end.
At a glance
Accounting- Why it matters
- UK statutory
- Related
- 3 terms
- Walkthroughs
- 3 guides
- Watch out
- Common misconception below
Plain English. UK spelling. No marketing filler.
Why this matters
Every UK limited company must file a CT600 each year, even if there is no tax to pay. The return reports trading profits, capital gains, losses brought forward, and reliefs claimed. The main rate is 25% on profits over £250,000; the small-profits rate of 19% applies under £50,000, with marginal relief between. Late filing triggers automatic penalties starting at £100 and climbing.
How YionStack handles it
The YionStack accounting module prepares the CT600 figures from the live ledger at year-end. Trading profit, capital allowances, R&D enhancement (if claimed), losses brought forward and the dividend record all derive from the same data that produced the statutory accounts. The direct HMRC CT API submission is on the build-plan roadmap; today, YionStack produces the CT600 working schedule and the iXBRL-tagged accounts that an accountant submits on the business’s behalf. The next-due-date is tracked on the business profile so the reminder fires automatically.
Common misconception
Filing and paying are two separate deadlines
Corporation tax is due nine months and one day after the accounting period end. The CT600 return itself is due twelve months after the period end. You pay before you file — most owners assume the opposite because Self Assessment works that way.
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