Corporation Tax is charged on the profits of UK limited companies and other incorporated entities. If your company is UK-resident, it is generally liable to Corporation Tax on worldwide profits. If your company is non-UK resident but operates a UK branch or permanent establishment, it is taxed only on profits arising from UK activities.
With Corporation Tax rates higher than they were historically, effective tax planning is essential. This guide explains how UK companies can legally reduce their Corporation Tax bill using proven, HMRC-compliant strategies.
UK Corporation Tax Rates Explained
The UK Corporation Tax system uses tiered rates depending on profit levels.
Corporation Tax Rates (2023–2025)
Small Profits Rate
- Profits up to £50,000
- Tax rate: 19%
Marginal Rate
- Profits between £50,001 and £250,000
- Effective rate: 5%
- Marginal Relief reduces the tax bill within this band
Main Rate
- Profits over £250,000
- Tax rate: 25%
Companies with associated companies must share these thresholds, which can significantly affect the rate applied.
Corporation Tax Filing and Payment Deadlines
Understanding deadlines is crucial to avoid penalties.
- Accounting period: Usually 12 months (cannot exceed 12 months)
- Corporation Tax return (CT600): Due 12 months after the end of the accounting period
- Corporation Tax payment: Due 9 months and 1 day after the end of the accounting period
If your accounting period exceeds 12 months, two CT600 returns are required.
Proven Strategies to Save Company Tax in the UK
1. Claim All Allowable Business Expenses
Allowable expenses are costs incurred wholly and exclusively for business purposes. These reduce taxable profits directly.
Common allowable expenses include:
- Staff salaries and employer NICs
- Office costs and utilities
- Professional fees (accountants, solicitors)
- Business insurance
- Marketing and advertising
- Travel expenses (business-related only)
Failing to claim legitimate expenses is one of the most common reasons companies overpay Corporation Tax.
2. Use Capital Allowances Effectively
Capital allowances provide tax relief on qualifying capital expenditure, such as plant and machinery.
Full Expensing (Temporary Relief)
From April 2023 to March 2026, companies can claim 100% first-year relief on qualifying plant and machinery.
This means:
- The full cost is deducted immediately
- Reduces Corporation Tax by up to 25p for every £1 invested
Annual Investment Allowance (AIA)
- Allows a 100% deduction on qualifying assets
- Annual limit: £1 million
Strategic timing of asset purchases can significantly reduce tax liabilities.
3. Claim Research & Development (R&D) Tax Credits
R&D tax relief rewards companies that invest in innovation, product development, or process improvement.
Eligible activities may include:
- Developing new products or software
- Improving existing processes
- Overcoming technological uncertainty
R&D relief can:
- Reduce Corporation Tax
- Generate a cash repayment for loss-making companies
This relief is often underclaimed due to complexity, despite being highly valuable.
4. Use the Patent Box Regime
The Patent Box allows companies to pay a reduced Corporation Tax rate on profits derived from qualifying intellectual property.
Key features:
- 10% effective Corporation Tax rate on qualifying profits
- Applies to worldwide income from patented inventions
- Encourages commercialisation of UK-developed IP
This relief is particularly valuable for technology, pharmaceutical, and manufacturing businesses.
5. Utilise Trading Loss Relief
UK loss relief rules allow companies to reduce tax by offsetting losses.
Carry Back Losses
- Trading losses can be carried back 12 months
- Offsets profits from the same trade
- Can generate a tax refund
Carry Forward Losses
- Losses are carried forward automatically
- Offset against future profits from the same trade
- Must be used at the earliest available opportunity
Example
If a company makes:
- £50,000 profit in 2022
- £100,000 loss in 2023
The loss can:
- Offset £50,000 of 2022 profits
- Leave £50,000 to carry forward
6. Consider Group Relief (Where Applicable)
Companies in the same group may be able to share losses, allowing one company’s losses to offset another’s profits — reducing the group’s overall tax bill.
This area is highly technical and requires careful structuring.
Common Corporation Tax Planning Mistakes
- Missing allowable expenses
- Failing to claim capital allowances
- Overlooking R&D eligibility
- Poor loss planning
- Ignoring associated company rules
- Late filing or payment penalties
Proactive planning avoids these issues.
Final Thoughts
Corporation Tax planning is not about avoiding tax — it’s about using the reliefs and allowances Parliament intended.
By:
- Claiming legitimate expenses
- Investing strategically
- Using R&D and capital allowances
- Planning for losses and profit thresholds
UK companies can significantly reduce their Corporation Tax bill, remain compliant, and improve cash flow.
For growing businesses, professional advice often pays for itself many times over.
FAQs
Do sole traders pay Corporation Tax in the UK?
No. Sole traders pay Income Tax and National Insurance, not Corporation Tax.
Can companies use past losses to reduce current tax?
Yes. Losses can be carried back or carried forward, subject to rules.
Can Patent Box relief be claimed retrospectively?
Claims generally apply to current and future periods, but past returns may sometimes be amended within statutory limits.
What is the Annual Investment Allowance (AIA)?
AIA allows a 100% deduction for qualifying plant and machinery up to £1 million per year
