Corporation Tax returns, done properly

A Company Tax Return is more than the CT600 form. A complete submission to HMRC includes the CT600 itself, tax computations showing how the taxable profit was calculated from your accounting profit, and your statutory accounts — all filed online in iXBRL format. The computations are where the real work happens: adding back disallowable costs (client entertaining, most fines), claiming capital allowances on equipment, and applying any reliefs and losses.

• 19% small profits rate — profits of £50,000 or less
• 25% main rate — profits over £250,000
• Marginal relief between £50,000 and £250,000 (effective rate tapers from 19% to 25%)
• Payment due: 9 months and 1 day after your accounting period ends
• Return due: 12 months after your accounting period ends

The £50,000 and £250,000 limits are divided between associated companies under common control — if you run more than one company, this often matters more than directors expect.

See the full Corporation Tax deadline guide →

A newly formed company that starts doing business must register for Corporation Tax with HMRC within 3 months of starting to trade — trading includes buying, selling, advertising, employing someone or earning interest. Most companies registering with Companies House online are enrolled for Corporation Tax at the same time; if yours wasn’t, or it has started trading after a dormant period, we can sort the registration as part of our service.

1. We prepare your year-end accounts (or work from accounts you already have)
2. We build the tax computation — adjustments, capital allowances, reliefs and any losses brought forward
3. We complete the CT600 and confirm your exact Corporation Tax bill and payment date
4. You approve; we file with HMRC in iXBRL and send you the acknowledgement

Because the accounts and the tax return draw on the same records, having one firm do both is faster and avoids inconsistencies HMRC systems flag.

Pair it with year-end accounts preparation →