Know the company’s taxable profit — before the payment deadline.
Britvex connects the company’s annual accounts, Corporation Tax computation, Company Tax Return and payment timetable so the tax position is built from the same financial information rather than treated as a separate year-end exercise.
The accounts show profit. The tax computation determines taxable profit.
Corporation Tax can apply to trading profits, investment income and chargeable gains. The taxable figure can differ from the accounting profit shown in the company’s annual accounts.
Business profits
Profits arising from the company’s trading activity form a core part of the Corporation Tax calculation.
Investment income
Relevant investment income received by the company can also form part of its Corporation Tax position.
Chargeable gains
Profits arising when a company disposes of certain assets can be subject to Corporation Tax as chargeable gains.
Tax treatment differs from accounting treatment
Some expenses, allowances and other items are treated differently for tax, which is why accounting profit and taxable profit can diverge.
Do not assume every company simply pays 19% or 25%.
The standard small profits rate is 19% and the main rate is 25%. Marginal Relief can apply between the standard £50,000 and £250,000 limits.
Accounts → Adjust → Calculate → File.
Corporation Tax starts with the company’s financial information, but the tax calculation needs separate adjustments before the final taxable position is reached.
Start from the company’s year-end figures.
Use the annual accounts and underlying records as the financial base for the Corporation Tax work.
Apply the relevant tax treatment.
Review expenses, allowances, gains and other items where the tax treatment differs from the accounting treatment.
Work out the taxable profit and Corporation Tax.
Apply the relevant rate, Marginal Relief and other applicable tax rules to the company’s position.
Complete the Company Tax Return.
Submit the Company Tax Return and keep the tax-payment position connected to the same year-end work.
The payment deadline usually comes before the filing deadline.
This distinction matters. A company can still be within the Company Tax Return filing period even though the standard Corporation Tax payment date has already passed.
The strongest year-end process keeps the accounts and tax computation together.
The accounts and Company Tax Return are separate obligations, but the work should not begin from two separate versions of the company’s financial year.
The tax return is often where earlier accounting problems become visible.
Britvex works backward to the underlying records rather than treating the CT600 as a standalone form.
Bookkeeping is incomplete
Missing transactions or unreconciled balances can change both the accounts and the taxable profit.
Accounting cost does not automatically equal tax deduction
The tax computation may need adjustments where an expense is treated differently for Corporation Tax purposes.
Capital expenditure needs separate tax treatment
Capital allowances and other rules can affect how spending on business assets enters the tax computation.
Payment date is missed while the return is still “not due”
The normal payment deadline is earlier than the normal Company Tax Return filing deadline, which can catch companies out.
Corporation Tax support built around the company behind the return.
Different companies create different tax adjustments, records and filing questions.
Limited Companies
Annual accounts, Corporation Tax and company compliance within one connected relationship.
Limited Companies →Startups & SMEs
Move from early trading into a repeatable year-end accounting and Corporation Tax process.
Startups & SMEs →Property Companies
Corporation Tax work for companies with property income, finance costs, assets and related transactions.
Property & Landlords →Overseas-Owned UK Companies
UK Corporation Tax and accounting support where the shareholders or directors are based abroad.
Overseas Founders →Tax work should be documented, reviewable and connected to the records behind it.
Britvex connects onboarding, documents, accounting and tax communication through a UK practice and secure client portal.
Before your Company Tax Return is due.
These are general rules. The exact Corporation Tax position depends on the company, accounting period and applicable tax rules.
What is the Corporation Tax rate in 2026?
For the standard regime, the small profits rate is 19% and the main rate is 25%. Marginal Relief may apply between the standard £50,000 and £250,000 profit limits.
Does every company with profits under £50,000 automatically pay 19%?
No. The small-profits rules have conditions, and the profit limits can be reduced where the company has associated companies or a short accounting period. Special regimes can also differ.
When is Corporation Tax normally paid?
For companies within the standard payment rules, Corporation Tax is usually due nine months and one day after the end of the accounting period.
When is the Company Tax Return due?
The normal filing deadline is 12 months after the end of the accounting period covered by the return.
Do I still file if the company made a loss?
If HMRC has issued a notice to deliver a Company Tax Return, the company must still file the return even if it made a loss or has no Corporation Tax to pay.
Is taxable profit the same as the profit in the annual accounts?
No. The tax computation can adjust the accounting profit for items that are treated differently for Corporation Tax purposes.
When does a new company need to tell HMRC it is active?
A company that becomes active and falls within Corporation Tax normally needs to tell HMRC within three months of the start of its tax accounting period if the Corporation Tax service has not already been correctly set up.
Know the tax before the company reaches the payment deadline.
Start with the annual accounts and underlying records. Britvex can prepare the Corporation Tax computation, identify the relevant adjustments, explain the tax due and keep the Company Tax Return connected to the wider year-end process.