You've filed your Self Assessment. HMRC owes you a CIS refund. Now you're watching your bank account and wondering: when is the money actually going to arrive?

The honest answer is: it depends. Most CIS subcontractors receive their refund within 2 to 8 weeks of HMRC processing their return. But "processing" is the key word — and there are several things that can shorten or stretch that window significantly.

This guide gives you the complete picture: the typical refund timeline, the most common reasons for delays, and the specific steps you can take right now to get paid faster.

The CIS Refund Timeline: Step by Step

A CIS tax refund doesn't happen automatically. HMRC doesn't know how much you're owed until you tell them — through your Self Assessment tax return. Here's exactly what happens, and when, once you file.

Paper vs Online: Why It Makes Such a Big Difference

Filing on paper is one of the single biggest reasons CIS subcontractors wait far longer than they need to for their refund. The difference isn't marginal — it's significant.

The paper deadline for Self Assessment is 31 October. But even if you file on paper in October, HMRC has until January to process it — meaning your refund could be delayed by months. Always file online.

The 5 Most Common Reasons a CIS Refund Is Delayed

If your refund is taking longer than expected, one of these is almost certainly the reason.

1. Your CIS deductions don't match what contractors reported

Every month, your contractor submits a CIS monthly return to HMRC listing what they've deducted from your payments. If the figure you declare on your Self Assessment doesn't match their records, HMRC will flag it. This is the most common cause of delays — and it's usually down to a missing deduction statement or a simple data entry error.

2. Your bank details aren't on your HMRC account

HMRC can only issue a BACS payment if your UK bank account details are saved in your online account. If they're not there — or if they're outdated — HMRC will send a cheque to your registered address. That adds 7 to 14 days, and if your address details are also wrong, the cheque may not arrive at all.

3. HMRC opened a compliance check

For a small proportion of returns, HMRC will open a compliance check before issuing the refund. This can happen if your expenses seem unusually high, your income level changed significantly, or the CIS figures are difficult to match against contractor records. A compliance check doesn't mean you've done anything wrong — but it can add weeks or months to the wait.

4. You filed for an older tax year

You can claim CIS refunds for up to 4 previous tax years. But older returns take longer — HMRC needs to cross-reference records that may be further back in their systems, and the return may require manual review.

5. You have outstanding tax debt or a Payment on Account balance

If you owe HMRC money from a previous year — or if you have a Payment on Account due — HMRC will offset your refund against that balance before paying you the remainder. If the debt exceeds your refund, you may not receive any payment at all. This catches many subcontractors off guard.

How to Speed Up Your CIS Refund: A Practical Checklist

You can't make HMRC move faster. But you can remove every reason for them to slow down. Work through this checklist before you file — and again if your refund is already overdue.

• File your Self Assessment online, not on paper
• File as early as possible after 6 April — don't wait until January
• Collect every CIS payment and deduction statement from every contractor before you file
• Check that the total CIS deductions on your statements match what you're declaring in Box 38 (SA103S) or Box 82 (SA103F)
• Log into your HMRC online account and confirm your UK bank account details are saved and current
• Check your registered address matches what HMRC holds — update it if you've moved
• Review whether you have any outstanding tax debt or Payment on Account due that HMRC might offset against the refund
• Claim all allowable expenses — tools, mileage at 55p/mile (first 10,000), PPE, phone — as these reduce your taxable profit and increase your refund
• Respond promptly to any HMRC correspondence — delays often compound when subcontractors ignore letters

When to File for the Fastest Possible Refund

Timing matters. HMRC's Self Assessment window opens on 6 April each year — the day after the tax year ends. The deadline for online filing is 31 January the following year. But filing early has a real advantage when it comes to refunds.

HMRC processes returns in the order they are received. Filing in April or May — when the system is quiet — typically results in faster processing than filing in December or January when millions of people are submitting at the same time.

How to Check the Status of Your CIS Refund

Once you've filed, you don't have to sit and wait in the dark. There are two ways to track your refund status.

• 1
  Log into your HMRC online account at gov.uk. Go to Self Assessment → View your tax calculation. If a refund has been issued, it will show as a credit on your account with a payment date.
• 2
  Call the Self Assessment helpline on 0300 200 3310 (Monday to Friday, 8am to 6pm). Have your UTR number ready. The helpline can confirm whether your return has been processed and whether a refund is pending.

Can You Claim CIS Refunds for Previous Tax Years?

Yes — and this is one of the most underused parts of the CIS system. HMRC allows you to claim refunds for up to 4 previous tax years. If you've been working in construction under CIS for several years and never filed a Self Assessment, there may be a significant amount waiting for you.

Each back year requires a separate Self Assessment return. The process is the same — but older returns are more likely to be subject to additional review, so allow extra time for the refund to arrive.

What Happens If HMRC Owes You Money But You Also Owe Tax?

This is a situation that catches many subcontractors off guard. If HMRC calculates that your CIS refund is £1,400 — but you also have £600 outstanding from a previous year or a Payment on Account — they will offset the debt first and pay you the remaining £800.

You won't receive a phone call about the offset — but HMRC will send you an official tax calculation (your SA302) showing exactly what was owed, what was deducted, and what refund remains. If the figure in your bank is lower than expected, log into your HMRC account and check your Self Assessment calculation — it will explain the difference line by line. This is why it's worth checking your HMRC account for any outstanding balances before you file, so there are no surprises when the money arrives.

Frequently Asked Questions