CIS | Subcontractors
How Much CIS Tax Refund Am I Owed in 2026? (And Why Claiming Now Beats Waiting Until January)
If you work under the Construction Industry Scheme, 20 per cent (or 30 per cent) is stopped out of every payment before it reaches you. By the time the tax year ends, HMRC is usually holding far more of your money than it is actually entitled to. The question every subcontractor asks is the same: how much will I get back?
The honest answer is that it depends on two things, your income and your expenses, but most subcontractors are owed a meaningful refund, often running into the thousands. The good news is that the 2025/26 tax year has now ended (5 April 2026), which means you can claim your refund right now. You do not have to wait until January.
This guide shows you exactly what drives the size of your refund, gives you realistic worked examples for different income levels, and explains why claiming now in the summer is far smarter than joining the January scramble. If you want the full step-by-step process, see our companion guide on how to claim a CIS tax refund.
Why You Are Almost Certainly Owed Money
Under CIS, contractors deduct tax from the labour part of your invoices and pay it straight to HMRC as an advance against your tax bill. The problem is that this flat deduction takes no account of two things that reduce what you actually owe:
- Your personal allowance of £12,570, which is completely tax-free. CIS deductions are taken as if every pound is taxable, which it is not.
- Your allowable expenses, the tools, travel, insurance and other costs that come off your profit before tax is calculated.
Because of these, the 20 per cent taken at source is almost always more than your real liability once your allowance and expenses are applied. The difference is your refund.
On 30 per cent deductions? That means you are not registered or verified as a CIS subcontractor. Register with HMRC to drop to 20 per cent, but in the meantime your overpayment is even larger, so your refund is likely to be bigger when you claim.
So How Much CIS Refund Will You Actually Get?
Four things decide the size of your refund:
- How much CIS was deducted over the year (your deduction statements show this).
- Your personal allowance (£12,570 tax-free for 2025/26).
- Your allowable expenses, the bigger and better-documented these are, the lower your taxable profit and the bigger your refund.
- Your income level, which sets how much tax and National Insurance you genuinely owe.
Here are three realistic examples for a registered subcontractor (20 per cent deductions) whose income all falls under CIS:
| Labour income | Expenses claimed | CIS deducted | Estimated refund |
|---|---|---|---|
| £24,000 | £3,000 | £4,800 | ~£2,600 |
| £40,000 | £6,000 | £8,000 | ~£2,430 |
| £55,000 | £8,000 | £11,000 | ~£2,050 |
Illustrative only. Assumes you are registered (20 per cent deductions), all income falls under CIS, expenses are claimed in full, Class 4 National Insurance is included, and no payments on account yet apply. Your actual refund will differ, which is exactly what we calculate for you free of charge.
Notice the pattern: even higher earners are owed a substantial refund, and the single biggest lever you control is your expenses. Every legitimate cost you fail to claim is money you hand to HMRC that you could have kept.
Harrow groundworker: £3,180 back in 12 days
Client M is a self-employed groundworker working for two main contractors across north-west London. Over 2025/26 he earned around £42,000 in labour, all under CIS, with roughly £8,400 stopped from his payments. He had never claimed properly before, his previous returns listed almost no expenses.
When we went through his year, we captured his van mileage to temporary sites, tools, protective clothing, public liability insurance, his phone, and a use-of-home allowance, around £7,600 of legitimate costs his old return had missed. That brought his taxable profit down and his real liability to roughly £5,220.
We filed in early June, well before the January rush. His refund of £3,180 landed in his account 12 days later. Had he waited until January, he would have been competing with millions of other returns and waiting considerably longer, all while HMRC sat on his money.
Why Claiming Now Beats Waiting Until January
Most subcontractors leave their tax return until the 31 January deadline out of habit. That is the worst possible time to claim a refund. Here is why claiming now, in the summer, is the smarter move:
- You get paid far faster. Refunds claimed between April and October often arrive in one to four weeks because HMRC is quiet. In January, when the whole country files at once, the same refund can take much longer. See our guide on how long a CIS refund takes.
- It is your money, not HMRC’s. Why leave £2,000 or £3,000 sitting in HMRC’s account for an extra nine months when you could have it working in your business or your pocket now?
- You can already claim 2025/26. The tax year ended on 5 April 2026, so the return is open and ready to file today.
- No January stress, no penalty risk. Filing now removes the deadline panic entirely and gives you certainty about your position months ahead of time.
- Better planning. Knowing your numbers early helps you plan for any payments on account and avoid surprises.
The deadline to file your 2025/26 return online is 31 January 2027, but there is no reward for waiting and a real cost to your cash flow. The earlier you file, the sooner you are paid.
Don’t Leave Money on the Table: Expenses Subcontractors Miss
Because expenses are the biggest driver of your refund, underclaiming them is the most common and most expensive mistake we see. Make sure your claim includes everything you are entitled to:
- Tools and equipment, bought or replaced during the year.
- Protective clothing and PPE, boots, hi-vis, hard hats, gloves.
- Travel to temporary sites, mileage at 45p per mile for the first 10,000 miles and 25p after that, or actual running costs, plus parking and public transport.
- Phone and internet, the business proportion of your bills.
- Materials you paid for yourself and were not reimbursed for.
- Public liability insurance and other trade insurance.
- Accountancy fees, yes, our fee is itself an allowable expense.
- Use of home for quoting, admin and record-keeping.
- Training, CSCS card and certifications that maintain your trade.
- Washing your own workwear and other smaller everyday costs that add up.
If you work in the trades, our accountant for tradesmen page explains how we make sure nothing legitimate is missed.
Can You Claim CIS Refunds From Previous Years?
Yes. You can generally go back up to four tax years to reclaim overpaid tax. If you never claimed properly in earlier years, or claimed without your full expenses, those refunds may still be recoverable. We can review your previous returns and tell you quickly whether there is more to come back to you.
FREE CALCULATOR · 2025/26 TAX YEAR
How much CIS refund are you owed?
Enter three figures from your CIS statements and see your estimate in 60 seconds.
🔒 Nothing is saved until you choose to send it. This is a guide only.
Want your exact figure? A real accountant in Stanmore confirms it free — just tell us where to send it.
Brilliant — that’s on its way to us.
We’ll review your figures and come back within one working day with your exact refund.
📅 Book my free 15-min callFree consultation calls: weekdays 1pm to 3pm and 7pm to 8pm.
Frequently Asked Questions
How much is the average CIS tax refund?
There is no single average, because it depends on your income and how much you claim in expenses. In practice most subcontractors we deal with are owed somewhere between a few hundred and several thousand pounds for a tax year. The amount is driven by how much CIS was deducted, your tax-free personal allowance of £12,570, and the expenses you claim.
Can I claim my CIS refund now or do I have to wait until January?
You can claim now. The 2025/26 tax year ended on 5 April 2026, so you can file your Self Assessment and claim your refund from 6 April 2026 onwards. You do not have to wait until the 31 January deadline, and claiming early usually means you are paid much faster.
How long does a CIS refund take if I claim early?
Refunds claimed early in the tax year, between April and October, often arrive within one to four weeks because HMRC is far less busy than in the January rush. Filing in January, when millions of returns hit HMRC at once, typically means a longer wait.
Will claiming early get me a bigger refund?
No. The size of your refund is the same whether you claim in May or January; it is set by your income and expenses, not the date you file. Claiming early simply means you get your money sooner and avoid HMRC delays. A bigger refund comes from claiming every allowable expense, which is where an accountant usually adds the most value.
What if I am on 30% CIS deductions instead of 20%?
A 30 per cent deduction means you are not registered or verified as a CIS subcontractor. You should register with HMRC to drop to 20 per cent, but in the meantime your overpayment is even larger, so your refund is likely to be bigger when you claim.
Do I need an accountant to claim a CIS refund?
No, you can file the Self Assessment yourself. However, most subcontractors who file alone underclaim their expenses and leave money with HMRC. A fixed-fee accountant typically recovers more than the fee costs and deals with HMRC for you.
Want to know your number?
At Your Tax Help Accountants in Stanmore, we work out exactly what HMRC owes you, make sure every expense is claimed, file your return and chase your refund, all for a fixed fee. We work with CIS subcontractors across Harrow, Wembley, Edgware and the whole of the UK. Claim now and get paid in weeks, not January.
Or email info@yourtaxhelp.co.uk | yourtaxhelp.co.uk
General guidance only. Not personal tax advice. Figures are illustrative and based on the 2025/26 tax year. Contact us for advice specific to your situation.