What Information Do I Need for CIS Tax Refund Claims?

To successfully claim your CIS tax refund, you’ll need several key documents that prove your income and tax deductions.

Essential paperwork includes all CIS statements from contractors, monthly payslips showing CIS deductions, P45 and P60 forms if applicable, and bank statements covering the relevant tax year.

Knowing what evidence to keep and for how long can help you claim back the highest legitimate tax refund and keep compliant with HMRC at the same time.

Our CIS guide provides contractors some clear guidance on what records are necessary to support your return and satisfy HMRC requirements.

CIS income and tax details

Knowing what you earned and how much tax you paid is the starting point for all CIS tax returns.

You can get your income and tax details from:

• Payslips or CIS statements from your contractor(s).
• P45 or P60 (if you had any PAYE employment).
• Bank statements.

It’s important to keep a record of all of your income. If you have had any PAYE employment, or received any benefits, these are normally included on your tax return as well.

This means that you should retain any P60 or P45 forms received from PAYE employment and any statements sent to you showing how much JSA or other benefits you received.

If you don’t enter all of your income and your tax return is investigated by HMRC you could owe tax and incur a penalty.

CIS tax return expenses

Your expenses as a CIS sub-contractor are very important to make sure you don’t overpay tax and will ensure you get back the maximum legitimate CIS refund.

Evidence of your expenses can come in different forms for example:

• Physical or digital receipts.
• Bank statements.
• A mileage log.
• MOT certificates.

Always try and remember to keep the receipts for all of your work related expenses.

The more expenses you can claim, the less tax you have to pay. A good rule of thumb is to keep evidence of everything to do with your self employment.

For those who haven’t yet switched to digital record-keeping, it’s advisable to track both expenditure and revenue electronically.

Most CIS subcontractors will be impacted by Making Tax Digital, requiring digital record formats. Beyond MTD requirements, either paper or digital records are acceptable.

How do I prove my vehicle expenses for my CIS tax return?

Vehicle expenses are a common one for CIS sub-contractors and require careful documentation to satisfy HMRC requirements.

Keep a detailed mileage log recording business journeys, including dates, destinations, purposes, and distances traveled.

You can claim either actual costs (fuel, insurance, repairs, MOT) with supporting receipts, or use HMRC’s approved mileage rates (AMAP).

Many sub contractors find the mileage rate method simpler, as it requires less paperwork while still providing substantial tax relief.

Remember, commuting to your regular workplace doesn’t count as a business expense.

My receipts are fading or getting damaged – what should I do?

Thermal receipts from many retailers fade over time, potentially causing problems if HMRC requests documentation.

The solution is to photograph or scan important receipts immediately after purchase, storing digital copies in organised folders on your computer or cloud storage.

Keeping all records digitally is recommended for all sub contractors because of making tax digital which is affecting most self employed individuals at some point in the future.

Sub contractors should consider using smartphone apps specifically designed for receipt management, which can categorise expenses automatically.

Keep both the original receipt and digital copy when possible, but prioritise creating clear digital backups of any receipts that might deteriorate.

I’ve lost some important documents – can I still claim my CIS refund?

Lost documentation doesn’t necessarily prevent you from claiming your CIS refund, but you’ll need to take action to replace missing items.

• Contact contractors directly to request duplicate CIS statements – they’re legally required to provide these.
• For lost P45 or P60 forms, contact your former employers or HMRC directly via your personal tax account.
• Bank statements can often substitute for missing receipts, especially when the transaction clearly shows a business purchase.

The key is being proactive about replacing documentation rather than hoping HMRC won’t notice gaps in your records.

What if my contractor hasn’t provided proper CIS statements?

Contractors are legally obligated to provide monthly CIS statements showing payments made and tax deducted.

If you haven’t received these, contact your contractor immediately in writing, keeping copies of your correspondence.

If they continue to refuse, you can report them to HMRC, as this is a serious compliance issue.

In the meantime, gather alternative evidence like contracts, invoices, and bank statements showing payments received.

While CIS statements are preferred, HMRC can work with other documentation if you can demonstrate you’ve made reasonable efforts to obtain the proper paperwork.

A common record keeping mistake

Some subcontractors forget to include all their income sources, focusing only on their main contractor relationships while overlooking smaller jobs, PAYE work, or benefits received.

HMRC has sophisticated systems that cross-reference your declared income with information they receive from employers and contractors.

Always gather documentation for every income source, no matter how small, to avoid complications and potential penalties.

How long should I keep my records for my CIS tax return?

HMRC states that you should keep record for a minimum of 5 years after the 31 January submission deadline of the relevant tax year.

The tax office can make an enquiry into your tax return and if they do they will usually want to see evidence of the expenses claimed.

It is recommended to keep electronic versions of any receipts with scanned copies or photos acceptable as long as they show all of the necessary facts and figures.

How can I make next year’s record-keeping easier?

Learning from this year’s challenges can make future CIS refund claims much simpler.

Set up a dedicated business bank account to separate personal and business expenses clearly. Use a smartphone app to photograph receipts immediately after purchase.

Try to create a simple monthly routine to file CIS statements and check you’ve received everything expected.

Consider using cloud storage to back up important documents automatically. Many contractors find that spending a few minutes each week organising paperwork saves hours of stress when completing their tax return.

Key Takeaways

Before you start your CIS tax return, here’s a quick summary of the income and expense records you’ll need, and how long to keep them.

• Two things matter for your CIS return: income and expenses. You’ll need proof of both to submit an accurate return.
• Confirm your income using payslips, your CIS statements, and — if you had PAYE work during the year — a P45 or P60; bank statements can support all of it.
• MOT certificates, logged mileage, bank statements, and receipts — whether on paper or saved digitally — can all support an expense claim. The stronger your evidence, the more you stand to legitimately get back.
• HMRC’s rule of thumb is a 5-year hold: count forward from 31 January following the tax year in question, and keep your paperwork until that anniversary passes, in case an enquiry lands.
• A physical original isn’t essential — a clear scan or photo works too, provided none of the important details are missing or hard to read.

CIS Tax Return Records FAQs

Below are answers to common questions about gathering and keeping records for your CIS tax refund.

Do I need paper receipts, or can I use photos and scans?

A clear photo or scanned copy is generally fine, so long as every important detail on it stays legible. It’s still worth holding onto the physical version too, just in case it’s ever asked for.

What happens if I’m missing some of my income or expense records?

Missing expense evidence generally just means you can’t claim for that item, so your refund may be lower than it should be. Missing income is more serious — if HMRC investigates and finds income you didn’t declare, you could owe additional tax plus a penalty.

How long do I actually need to keep my CIS records for?

Think of it as a five-year window that starts ticking on 31 January after the tax year ends — until that point passes, HMRC can still come back and ask questions about your return.

I’ve had both CIS and PAYE work this year — do I need records for both?

Yes — a tax return usually combines everything you’ve earned in a year, so employed income needs the same paper trail as your CIS income. Hang on to your end-of-employment forms (P45 or P60) and any letters confirming benefit payments you received, and file them alongside your contractor statements.

What if I don’t have a mileage log — can I still claim travel expenses?

The page lists a mileage log as one accepted form of evidence, but bank statements or fuel/parking receipts can also help support a travel expense claim if a formal log wasn’t kept — the key principle is being able to evidence the cost.

Why does keeping good records affect the size of my refund?

Your refund is based on the gap between tax already deducted and tax actually owed once expenses are accounted for. The more legitimate expenses you can evidence, the lower your taxable profit, and the larger your potential refund.