Corporation Tax (CT600) Filing

If you run a UK limited company, you've gotta file a Corporation Tax return every year. This means submitting something called a CT600 form to HMRC (His Majesty's Revenue & Customs), along with your company accounts and tax computations. CT600 filing deadline is 12 months after the end of your accounting period, while payment deadline is 9 months and 1 day after the accounting period end (gov.uk file company tax return). Corporation Tax rates from April 2023: 19% for profits up to £50,000, 25% for profits over £250,000, with marginal relief for profits between £50,001 and £249,999 (gov.uk corporation tax rates).

The problem is most companies don't understand their CT600 obligations properly. They miss deadlines, make calculation errors, or don't claim all the reliefs they're entitled to. That causes problems—late filing penalties, late payment interest, incorrect tax calculations, and missed opportunities to reduce tax legally.

We handle Corporation Tax CT600 filing for companies needing proper tax compliance: CT600 form preparation (completing the official HMRC CT600 form correctly), company accounts preparation (preparing statutory accounts that support your CT600 return), tax computations (calculating Corporation Tax liability correctly, including all reliefs and allowances), payment deadline management (ensuring Corporation Tax is paid on time to avoid interest), and online filing (submitting your CT600 return via HMRC's online portal). Whether you're a company in Medway with straightforward profits, a company in Maidstone needing tax planning, or a company in Canterbury dealing with complex reliefs, we'll handle your CT600 filing that works. No penalties, no interest charges—just proper tax compliance that keeps you on the right side of HMRC.

What this helps you do (fast)

• Meet your Corporation Tax obligations — File your CT600 return correctly and on time, avoiding penalties and interest. Proper filing means no HMRC enquiries or compliance issues.
• Calculate Corporation Tax correctly — Ensure all reliefs, allowances, and deductions are claimed properly. Accurate calculations mean you pay the right amount of tax.
• Avoid penalties and interest — File and pay on time to avoid late filing penalties (£100+) and late payment interest (currently 8% annually). Avoiding penalties saves money and stress.
• Claim all available reliefs — Make sure you're claiming capital allowances, R&D relief, loss relief, and other available tax reliefs. Maximising reliefs reduces your tax bill legally.
• Understand your tax position — We'll explain your Corporation Tax liability, payment deadlines, and what reliefs apply to your situation. Understanding your tax position helps you plan and budget better.
• Stay compliant with HMRC — Proper CT600 filing keeps you compliant with HMRC requirements, reducing the risk of enquiries or investigations.

How it works

Step-by-step process for Corporation Tax CT600 filing:

1. Discovery call — We chat about your company: what your accounting period is, how much profit you've made, whether you have any capital allowances or reliefs to claim, what your filing deadline is, and what you want to achieve.
2. Company accounts preparation — We prepare your company accounts:
   • Profit and loss account — Income, expenses, and profit/loss for the accounting period
   • Balance sheet — Company assets, liabilities, and equity at the period end
   • Directors' report — Required company information and declarations
   • Notes to accounts — Supporting information and explanations
   Company accounts must be prepared in accordance with UK accounting standards and support your CT600 return.
3. Tax computations — We calculate your Corporation Tax:
   • Adjusted profit calculation — Start with accounts profit, adjust for disallowed expenses and non-taxable income
   • Capital allowances — Calculate capital allowances on qualifying assets (plant, machinery, equipment, etc.)
   • Relief claims — Apply available reliefs (R&D relief, loss relief, group relief, etc.)
   • Taxable profit — Calculate final taxable profit after all adjustments and reliefs
   • Corporation Tax calculation — Calculate tax at appropriate rate (19%, 25%, or marginal relief rate)
   Tax computations show how your accounts profit translates into taxable profit and Corporation Tax due.
4. CT600 form completion — We complete your CT600 return:
   • Company details — Company name, registration number, unique tax reference, accounting period
   • Income and expenses — Report all income and expenses from your accounts
   • Capital allowances — Report capital allowances claimed
   • Relief claims — Report any relief claims (R&D, losses, group relief, etc.)
   • Tax calculation — Complete tax calculation section with final Corporation Tax due
   • Additional pages — Complete any supplementary pages required (capital gains, loan relationships, etc.)
   CT600 form must be completed accurately with all relevant information from your accounts and computations.
5. Payment deadline management — We manage your payment:
   • Payment deadline calculation — Calculate payment deadline (9 months and 1 day after accounting period end)
   • Payment planning — Help you plan for Corporation Tax payment (installments if required for large companies)
   • Payment confirmation — Confirm payment has been made to HMRC on time
   • Payment reference — Ensure payment includes correct reference to match against your return
   Payment deadline management ensures Corporation Tax is paid on time to avoid interest charges.
6. Online filing — We file your CT600 return:
   • HMRC online portal — Submit return via HMRC's Government Gateway with CT600 filing role
   • Return submission — Upload CT600 form, accounts, and computations together
   • Filing confirmation — Receive HMRC confirmation of successful filing
   • Filing deadline — Ensure return is filed within 12 months of accounting period end
   Online filing ensures your CT600 return is submitted correctly and on time.

We handle all aspects of Corporation Tax CT600 filing. The key is preparing accurate accounts, calculating tax correctly with all reliefs, completing the CT600 form properly, paying on time, and filing within the deadline, so you stay compliant and avoid penalties.

Costs & timelines

Pricing factors:

• Accounts complexity — Simple companies (few transactions, straightforward income/expenses) cost less than complex companies (multiple income streams, complex transactions, group structures)
• Tax computations — Companies with capital allowances, R&D relief, loss relief, or other complex reliefs require more work
• Company size — Larger companies (more transactions, more complexity) generally cost more than smaller companies
• Additional services — Companies needing additional services (payroll, VAT, bookkeeping) may get package discounts

Commonly reported ranges by local providers:

• Small company CT600 filing (simple): £400–£800 for basic CT600 return with straightforward accounts and tax computations
• Medium company CT600 filing (standard): £800–£1,500 for typical CT600 return with accounts, computations, and some relief claims
• Large company CT600 filing (complex): £1,500–£3,000+ for complex CT600 returns (multiple reliefs, group structures, complex transactions, R&D claims)
• CT600 filing with annual accounts: £600–£1,200 for CT600 return plus full annual accounts preparation

Why Corporation Tax CT600 filing costs what it does:

• Company accounts preparation requires time to prepare profit and loss, balance sheet, and supporting notes in accordance with UK accounting standards
• Tax computations require detailed calculations including adjusted profit, capital allowances, relief claims, and Corporation Tax calculations
• CT600 form completion requires careful completion of all relevant sections with accurate information from accounts and computations
• Payment and filing management requires tracking deadlines, ensuring payments are made, and returns are filed on time
• Professional expertise ensures compliance with HMRC requirements and minimises risk of errors or penalties

Timeline: For returns filed before the deadline, preparation usually takes 2-4 weeks from when we receive all your company records. We'll need your records at least 4-6 weeks before the filing deadline to ensure on-time filing. For the payment deadline (9 months after period end), we'll need records earlier to calculate tax and ensure payment is made on time.

Payment: Corporation Tax must be paid by 9 months and 1 day after your accounting period end. Large companies (profits over £1.5 million) may need to pay in quarterly installments. We can help you understand payment requirements and set up payment plans if needed.

No hidden fees. CT600 filing price includes accounts preparation, tax computations, CT600 form completion, payment management, and online filing. Additional services (payroll, VAT, bookkeeping) are separate if you want them.

Kent (UK) focus

We work with companies across Kent: companies in Medway needing CT600 filing, companies in Maidstone with complex tax situations, and companies in Canterbury requiring tax planning.

Kent companies face the same Corporation Tax obligations as everyone else—filing CT600 returns, paying Corporation Tax on time, and claiming available reliefs. The difference is when you get proper help with CT600 filing, you prepare accurate accounts, calculate tax correctly, and file on time. That's what helps Kent companies stay compliant and avoid penalties.

Common Kent company scenarios:

• Small companies — Companies with profits under £50,000 needing straightforward CT600 filing
• Medium companies — Companies with profits between £50,000-£250,000 needing marginal relief calculations
• Companies with capital allowances — Companies investing in plant and machinery needing capital allowance claims
• Companies with R&D activities — Companies with research and development activities needing R&D relief claims

Kent business market context:

• Many Kent businesses are limited companies requiring annual CT600 filing
• Proper CT600 filing helps Kent companies stay compliant and avoid penalties
• On-time filing and payment helps Kent companies avoid interest charges and HMRC enquiries

Remote-first, Kent-focused. We don't need to meet in person (though we can if you prefer), and we understand what Kent companies are dealing with. CT600 filing, Corporation Tax calculations, payment deadlines, relief claims—we'll handle your Corporation Tax compliance that keeps you on the right side of HMRC.

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