Getting your paperwork in order before filing a tax return sounds dull, but it’s the one thing that saves you stress, time and, in many cases, money. Most contractors leave it late, then scramble around for receipts, invoices and CIS statements. What starts as a small delay quickly turns into missing deductions, HMRC letters and sometimes penalties.
Here’s the thing. Good record-keeping doesn’t need to be complicated. With a simple system, you can stay ahead of HMRC and make sure you claim everything you’re entitled to.
If you’re unsure whether you even need to file a return this year, you may want to check our guide on whether you need to file if you’ve had no income, which clears up the most common misunderstandings contractors face.
Let’s break it down into a clear, tradesperson-friendly guide you can actually follow.
Why organising your documents matters
Most UK contractors, especially those under CIS deal with a mix of paperwork. You might have digital receipts on your phone, payslips from part-time PAYE work and paper invoices from suppliers. When it’s scattered, things get missed.
Organised records help you:
- Claim every legitimate expense
- Track CIS deductions properly
- Avoid HMRC queries and penalties
- File faster and with fewer mistakes
- Keep your accountant from chasing you
And most importantly, the better your paperwork, the higher your potential tax refund.
Start by sorting your income
For most contractors, income falls into three buckets:
1. CIS income
This includes everything you’ve been paid as a subcontractor. You should gather:
- CIS monthly payslips
- Deduction statements
- Remittance advice
- Bank statements showing payments
If you’ve lost CIS statements, don’t panic. Ask the contractor who paid you legally, they must provide duplicates.
2. PAYE income
If you worked any employee role during the tax year, you’ll need:
- P60 (shows total pay and tax for the year)
- P45 (from any job you left during the year)
- Monthly payslips
HMRC cross-checks your PAYE details, so everything needs to match.
3. Other income
This applies if you earned money outside CIS/PAYE:
- Side jobs
- Online work
- Rental income
- Interest or dividends
Many people forget these and end up getting corrected later by HMRC.
Next, gather your expenses
Here’s what this really means. If you spent money to do your job, you can usually claim it. But HMRC wants proof.
Create a simple folder (physical or digital) and divide it into categories:
Tools and equipment
Keep receipts for:
- Power tools
- Small tools
- Repairs and replacements
If you’ve bought anything expensive, store the invoice separately so it doesn’t get lost.
Workwear and protective gear
Save receipts for boots, gloves, waterproofs and anything safety-related.
Travel
HMRC accepts:
- Fuel receipts
- MOT and servicing
- Insurance
- Parking
- Tolls
Mileage logs are helpful if you use the standard rate.
Materials you bought for jobs
These often get missed, but add up quickly.
Phone
Download monthly bills. Highlight the work-related portion if mixed use.
Home office costs
If you write invoices, store tools or handle admin from home, you may be able to claim part of your utility bills or use HMRC’s flat rate.
Insurance, memberships and training
These are valid business expenses, so don’t forget them.
Create a simple filing system you’ll actually use
You don’t need accounting software. A basic structure works:
Option 1: Digital folders
Create a folder on your phone or computer:
- 2024–25
- Income
- Expenses
- Tools
- Travel
- Materials
- Insurance
- Phone
- CIS
- PAYE
- Other paperwork
Take pictures of receipts as soon as you get them and drop them in the right folder.
Option 2: Paper folder
Get a big envelope or expanding file and label it. Every time a receipt lands in your pocket, drop it in there at the end of the week.
The goal isn’t perfection. It’s consistency.
Don’t forget your HMRC documents
You’ll need:
- Government Gateway login
- UTR number
- National Insurance number
- Any correspondence from HMRC
If you’ve lost your Gateway details, get them sorted early. Waiting until January is a guaranteed headache.
How far back do you need to keep documents?
HMRC expects you to keep business records for at least 5 years after the tax return deadline.
So if you’re filing for 2023–24, keep everything until at least January 2030.
Common mistakes contractors make
1. Not claiming small purchases
Screws, sandpaper, tape, drill bits. It adds up.
2. Losing CIS statements
Without them, HMRC cannot confirm your deductions.
3. Mixing personal and work transactions
It creates confusion and slows everything down.
4. Forgetting cash purchases
Always write down what it was for and take a photo.
5. Leaving everything until the deadline
You spend more time trying to remember than organising.
If CIS refunds are a big part of your return, you might also find our guide on tracking your CIS refund online helpful it explains what HMRC looks for and why delays happen.
What to do once everything is organised
You’ve got two options:
File it yourself
If your records are clean, filing your Self Assessment is straightforward.
Hand it over to a tax specialist
This is where most contractors get the best results. A professional spots things you may miss and ensures you claim everything you’re entitled to.
If you want to avoid errors, check out our breakdown of the most common CIS rebate rejection reasons, which helps you understand what HMRC flags most often.
If you’d rather avoid the hassle, Tax2u can take your documents and handle the whole filing process for you, including checking whether you’re due a refund.
Frequently Asked Questions
Do I need all original paper receipts?
No. Photos or digital copies are fine as long as they’re clear.
What if I can’t find some of my documents?
You can often get duplicates from contractors, employers, banks or suppliers.
Can I claim expenses without receipts?
HMRC prefers records. You may still claim some expenses, but it’s always safer to have proof.
Do CIS and PAYE records need to be separated?
Yes. They’re treated differently when filing your return, so keeping them separate avoids mistakes.
If you want someone to review your documents and make sure you’re getting the highest refund possible, try Tax2u’s Self Assessment service