CIS Tax Returns & Rebates Explained

If you work in the Construction Industry Scheme (CIS), you’ll know that a self-assessment tax return is an annual requirement. Many contractors mistakenly believe they need to wait until the January 31st deadline to file. In reality, you can submit your return any time from April 6th onwards.

Submitting sooner not only avoids the stress of the deadline rush but could also unlock a tax rebate much faster, especially if you’ve incurred allowable expenses. Let’s break down what you can (and cannot) claim for, explain why record keeping matters, and how early filing works in your favour.

Why File Your Self-Assessment Early?

The UK tax year runs from 6 April to 5 April. As soon as the new tax year begins on April 6th, you can complete and submit your return for the previous year. Waiting until January 31st of the following year isn’t necessary.

Filing early means you get faster rebates (if you’ve overpaid tax through CIS deductions). Filing earlier means you’ll see that money sooner. You’ll also avoid penalties – leaving your return until the last minute risks errors, missing information, or late submission fines.

What Expenses Can CIS Contractors Claim?

Claiming allowable expenses correctly is key to maximising your rebate. HMRC allows you to claim tax relief on costs that are “wholly and exclusively” for business purposes. Below are the most common categories:

1. Tools, Equipment and Protective Clothing

• Purchase, repair or replacement of tools.
• Protective clothing such as hard hats, steel-toe boots, hi-vis jackets, or overalls.
• Uniforms that identify your role (specialised workwear only, not everyday clothing).

2. Capital Expenses

• Work-related laptops, phones, and tablets.
• Vehicles purchased for business purposes (vans, cars, etc.).
• Running costs for business-use vehicles such as fuel, insurance, servicing, and road tax.

Note: If a vehicle is used partly for personal journeys, only the business-use portion of expenses can be claimed.

3. Travel and Subsistence

• Mileage claims for business travel (excluding your commute).
• Meals and accommodation when working away from home.

4. Administrative Costs

• Mobile phone and internet bills (business use only).
• Stationery and office supplies.
• Public liability insurance.
• Membership fees for professional bodies or trade unions.

What You Cannot Claim

Not every cost counts as an allowable expense. Submitting ineligible claims could land you in trouble with HMRC. Common items you cannot claim for include:

• Everyday clothing (jeans, t-shirts, trainers, etc.).
• Travel to a permanent workplace
• Personal use of vehicles, phones, or equipment
• Meals at home
• Non-business-related subscriptions or memberships.

Keeping these distinctions in mind ensures you stay compliant while still maximising your rebate though our expert team will guide you to ensure you claim correctly.

The Importance of Accurate Record Keeping

HMRC requires you to keep accurate records of your income and expenses. That means saving receipts, invoices, mileage logs, and bank statements. Records should be stored safely for at least five years after the 31 January submission deadline for the relevant tax year. (Note that new rules are being introduced which require digital record keeping, more information coming soon.

Next Steps

Filing your self-assessment doesn’t have to be stressful or left until the last minute. By acting early, keeping accurate records, and understanding what you can and cannot claim, you’ll not only stay compliant with HMRC but also improve your cash flow with rebates paid directly back to you.

If you’d like tailored support with your return – or to make sure you’re claiming every allowable expense – our team is here to help.  Please get in touch on 01923 257257.