Making Tax Digital

Making Tax Digital for Construction Workers: The CIS Subcontractor Guide 2026

Written byKarishma Thapa MagarKarishma Thapa MagarWritten byKarishma Thapa Magar is an ACCA Finalist with experience providing UK accountancy and taxation solutions to clients. She brings strong analytical and problem-solving skills to the table and is able to advise landlord and sole trader clients on the upcoming MTD requirements.View profile

Published on: 8 Apr 2026Updated on: 10 Jul 202610 min read

Making Tax Digital

MTD for Income Tax applies to CIS subcontractors in the same way it applies to any other sole trader. If your gross qualifying income is above £50,000, the rules have applied to you since 6 April 2026In practice that means keeping digital records, sending four quarterly updates to HMRC and filing a final declaration each year. The first quarterly update of the 2026/27 tax year is due by 7 August 2026.

HMRC will not chase every subcontractor individually, and many will not realise the rules apply to them until a deadline has passed.

This guide covers how your qualifying income is measured against your gross pay before CIS deductions, where those deductions fit into the reporting cycle, and what to do whether you are already mandated or approaching the £30,000 threshold that applies from April 2027.

What does MTD mean for CIS Subcontractors?

Making Tax Digital for Income Tax(MTD ITSA) is HMRC's initiative to move the UK tax system online. The goal is straightforward: reduce errors, improve accuracy, and give both taxpayers and HMRC a clearer, more real-time picture of income and tax liabilities.

It applies to sole traders and landlords who are registered for Self Assessment and earn above the qualifying income threshold.

Under MTD, sole traders and landlords must meet three obligations that replace the traditional annual return:

• Keep digital records of your self-employment and property income and expenses throughout the year

• Send quarterly updates to HMRC summarising that income and those expenses, four times per tax year

• Submit a final declaration by 31 January following the end of the tax year, where your total tax liability is calculated and confirmed

Does MTD Apply to CIS Subcontractors?

Yes, MTD for CIS subcontractors applies when all of the following conditions are met:

You must be an individual registered for Self Assessment

You must receive income from self-employment, property, or both

Your qualifying income must exceed the threshold for the relevant tax year

HMRC will write to you if your qualifying income crosses the threshold, but receiving or not receiving that letter does not change your legal obligation. Checking your own qualifying income remains your responsibility regardless.

What Is the Construction Industry Scheme?

Under CIS, contractors deduct tax from payments to subcontractors and pass it directly to HMRC, at 20% for registered subcontractors and 30% for unregistered ones.

They are advance payments set against your income tax liability for the year, and if too much has been deducted you are entitled to a refund.

Because HMRC treats CIS subcontractors as self-employed sole traders, you fall within MTD once your income crosses the threshold, and the deductions your contractors have already made are reconciled at the end of the MTD reporting cycle.

HMRC determines your entry point from the Self Assessment return for the previous tax year. If your gross income from self-employment and property in the 2024 to 2025 tax year was above £50,000, your MTD obligations began on 6 April 2026. If your 2025 to 2026 return shows qualifying income above £30,000, you are mandated from 6 April 2027.

The Rollout Timeline

1

6 April 2026

Over £50,000; Qualifying income in the 2024 to 2025 tax year

2

6 April 2027

Over £30,000; Qualifying income in the 2025 to 2026 tax year

3

6 April 2028

Over £20,000; Qualifying income in the 2026 to 2027 tax year

Worked Example

HMRC determines your entry point by reviewing the Self Assessment return you submitted for the previous tax year. So if your gross income from self-employment and property in the 2024 to 2025 tax year exceeded £50,000, you are required to use MTD from 6 April 2026.

How CIS Subcontractors Work Out Their Qualifying Income

This is where many subcontractors get tripped up, and it is an area where most published guidance falls short of giving a complete answer.

Your qualifying income is your gross income, meaning your turnover before any expenses are deducted. This matters enormously for CIS workers because the CIS deductions your contractor makes from your payments do not reduce your qualifying income figure. HMRC assesses what you were paid before those deductions, not what you received after them.

Your gross self-employment income counts in full, as does UK and foreign property income if you are a UK tax resident, including your share of income from jointly owned property.

Employment income taxed through PAYE, partnership profit shares, dividends and pension income do not count. The full breakdown of what falls inside and outside qualifying income is set out in our guide to Making Tax Digital for Income Tax Self Assessment.

Worked Example

If you earn £52,000 in gross self-employment income and £10,000 from a rental property, your qualifying income is £62,000, even if your contractor has already deducted CIS tax throughout the year and even if your actual take-home figure is considerably lower.

What MTD for CIS Subcontractors Actually Requires

Once you are in scope, three practical requirements apply throughout the tax year.

Digital Record Keeping Requirements for CIS Subcontractors

You must keep digital records of your CIS-related self-employment income and expenses, including payments received from contractors and any deductions made under the Construction Industry Scheme. If you also receive property income, you must keep digital records of that rental income and any allowable property expenses separately.

You do not need to create digital records for other income sources such as pensions or savings, but those sources must still be reported when you submit your final declaration.

There are two software routes available.

• Record-keeping software: connects to your business bank account, allows you to scan receipts, or lets you enter transactions manually

• Bridging software: connects to records you already keep in spreadsheets and makes submissions to HMRC on your behalf

Common Misconception

A common misconception in the industry is that spreadsheets are no longer acceptable under MTD. That is not accurate. Spreadsheets remain a valid record-keeping tool provided they are used alongside recognised bridging software that handles your submissions to HMRC.

How Quarterly Updates Work Under MTD for CIS

You send four quarterly submissions per tax year. Each quarterly submission is a summary of your CIS-related income and expenses, and any property income and expenses, up to that point.

These are not tax returns. They do not calculate or confirm your final tax liability. They give HMRC a rolling picture of your financial position throughout the year.

Updates must be submitted using HMRC-recognised software.

Standard Quarterly Periods

By default, your updates follow the tax year quarters with submission deadlines one month and five days after each period ends:

6 April to 5 July	Due by 7 August
6 July to 5 October	Due by 7 November
6 October to 5 January	Due by 7 February
6 January to 5 April	Due by 7 May

Calendar Quarter Option

You can elect to use calendar quarters instead, which aligns more naturally with how many businesses record their finances:

1 April to 30 June	Due by 7 August
1 July to 30 September	Due by 7 November
1 October to 31 December	Due by 7 February
1 January to 31 March	Due by 7 May

Both options share the same submission deadlines. The calendar quarter option must be selected in your software before your first update of the tax year is submitted.

Cumulative Submissions

It is also worth noting that each submission is cumulative rather than an isolated three-month snapshot, covering the period from 6 April to the end of that quarter. This means errors from a previous quarter carry forward automatically into the next submission rather than requiring a resubmission. Even if you have no income or expenses in a given quarter, a nil update must still be submitted.

MTD Final Declaration: What CIS Subcontractors Need to Submit

The final declaration is due by 31 January following the end of the tax year, and any tax owed is payable by the same date. This is where your total tax position is established. You add income not included in your quarterly updates, such as pensions, dividends or savings, claim any remaining reliefs and allowances, and your software calculates the final liability.

For CIS subcontractors, this is also where your deductions are settled. The tax your contractors deducted during the year is set against your final liability. If the deductions are more than you owe, which is common where the 20% rate has applied to gross payments while allowable expenses have reduced your actual profit, the final declaration is where your refund is established.

Choosing Software as a CIS Subcontractor

HMRC does not recommend any specific software product. They only ask that the MTD-compatible software of your choosing has passed HMRC's recognition process.

All products listed on the HMRC software finder have been through that process.

When choosing software as a CIS subcontractor, the key features to look for are:

• Support for self-employment income under CIS

• Quarterly update submission and final declaration submission capability

• The ability to handle multiple income sources if you also have property income

• Mobile access if you are regularly on site rather than at a desk

If you already keep your records in a spreadsheet and are comfortable with that system, bridging software allows you to continue doing so while meeting your MTD submission obligations. You do not need to start from scratch with a new record-keeping system if your existing one works for you.

Comparing Your Software Options as a CIS Subcontractor

The table below covers the features most relevant to subcontractors across commonly used MTD software options. Verify current features directly with each provider before committing.

You can explore our MTD software finder to find various MTD compatible software and choose the best for your business.

Penalties for MTD for CIS Subcontractors

HMRC will not issue penalty points for late quarterly updates during the 2026/27 tax year, for both mandated and voluntary taxpayers, as confirmed at the Autumn Budget 2025.

The concession covers late quarterly updates only. A late tax return is still penalised, and so is tax paid after 31 January 2027.

Outside the grace year, late submissions earn penalty points, with a £200 penalty once four points accumulate, and late payments attract percentage based penalties that increase the longer the tax remains unpaid.

The full framework, including point thresholds, reset conditions and current late payment rates, is in our MTD penalties guide.

For CIS subcontractors the main risk is cash flow. Earnings are often irregular and your refund position is only established at the final declaration, so a January payment can land at an awkward moment.

A Time to Pay arrangement agreed with HMRC before the penalty date avoids late payment penalties entirely. Agreeing it before the deadline, rather than after a penalty has been triggered, is the part that matters.

How to Prepare Before April 2026

Benefits of MTD for CIS Subcontractors Going Digital

The compliance requirements of MTD are real, but so are the practical benefits for self-employed construction workers who set up properly.

Knowing your income and approximate tax position at the end of each quarter is genuinely useful when your earnings fluctuate from job to job. It removes the year-end shock of discovering a larger than expected tax bill in January. It also means your allowable expenses, materials, tools, travel, and other costs are tracked and recorded throughout the year rather than scrambled together from memory in the final weeks of January.

Digital records are also considerably harder to lose than paper CIS statements and faded receipts. For construction workers who move between sites and manage multiple contractors, having everything stored in one digital system provides a level of organisation that the paper-based approach rarely achieves in practice.