Making Tax Digital Is Here. Are You Ready — or Are You About to Miss the Deadline?
From April 2026, HMRC is replacing the annual Self Assessment scramble with quarterly digital reporting. For CIS subcontractors above £50,000 gross income, this is no longer optional. Missing it means penalties — and missing out on the one genuine benefit it offers.
Every January, the same thing happens. Receipts come out of the glovebox, bank statements get pulled up, and a year's worth of invoices gets pieced together under pressure. For CIS subcontractors it's worse: deductions to reconcile, materials to separate from labour, and a tax bill that's often larger than expected because the 20% CIS deposit didn't cover everything.
Making Tax Digital (MTD) for Income Tax Self Assessment changes that structure entirely — quarterly updates instead of one annual filing, digital records instead of paper, and a running view of your liability instead of a January surprise. For subcontractors already dealing with CIS complexity, getting on top of MTD early is one of the most practical things you can do for your cash flow in 2026.
MTD Rollout Timeline
Gross income thresholds — based on the previous tax year's total turnover, not profit
What Actually Changes — and What Doesn't
The Self Assessment tax return doesn't disappear. What changes is the process that feeds into it. Instead of collating everything in January, you submit four quarterly updates throughout the year — a summary of income and expenses for each quarter — followed by a Final Declaration that closes out the year.
You must use HMRC-recognised software that connects directly via API. A standard Excel spreadsheet without bridging software no longer qualifies. This is the single most important practical change for subcontractors who've been doing their own books manually.
Old system: Darek files Self Assessment in January. He collects 12 months of receipts, reconciles his CIS deductions, and finds he owes £2,200 on top of his CIS deposits — money he hadn't set aside. He pays with a credit card.
With MTD: Darek's software logs income and expenses each week. By the end of Q1 he can already see his estimated liability for the year. He sets aside the right amount each month. In January, the Final Declaration is mostly already done. No surprises. No credit card.
Quarterly Deadlines: When Updates Are Due
| Quarter | Period Covered | Submission Deadline |
|---|---|---|
| Q1 | 6 April – 5 July | 7 August |
| Q2 | 6 July – 5 October | 7 November |
| Q3 | 6 October – 5 January | 7 February |
| Q4 | 6 January – 5 April | 7 May |
| Final Declaration | Full tax year | 31 January (as before) |
Missed updates trigger HMRC's points-based penalty system. Each missed submission earns one penalty point. Reach the threshold for your filing frequency and a £200 fixed penalty applies — with further penalties for continued non-compliance. Unlike the old system, there is no grace for occasional lateness once the points accumulate.
Bridging Software or Full Accounting Platform?
This is the practical decision most subcontractors need to make now. Both routes comply with MTD — but they suit different working styles and budgets.
Bridging Software + Spreadsheet
- Lower monthly cost (typically £5–£15/month)
- Keep your existing spreadsheet layout
- Bridging tool connects it to HMRC's API
- More manual input required each quarter
- No automatic CIS tracking or expense categorisation
- Works if your records are already well-organised
Full Cloud Accounting Software
- Xero, QuickBooks, FreeAgent, Sage — all MTD-ready
- Automatic CIS deduction tracking on invoices
- Receipt capture via phone camera
- Live tax liability estimate updated as you work
- Quarterly submissions handled inside the app
- Most offer free trials — test before committing
For subcontractors managing CIS deductions, materials splits, and mileage alongside regular income, a full accounting platform earns its monthly cost quickly — both in time saved and in errors avoided at quarter-end.
MTD Readiness Checklist: Do This Now
Add up all invoices raised — not what you received after CIS deductions, but the total gross figures on your invoices. If the total exceeds £50,000, you are in scope from April 2026. If it's between £30,000 and £50,000, you have until April 2027 — but starting now is still the right move.
Don't wait until the first quarterly deadline. Most platforms offer 30-day free trials — use one now to understand how it handles CIS invoices, expense categories, and quarterly submissions. The learning curve is much easier when there's no deadline pressure.
Every fuel receipt, tool purchase, PPE item, and training cost — photograph it the same day with your accounting app. The paper version is already unreadable by January. A digital record created in real time is both more accurate and HMRC-compliant.
Mixing personal and business transactions is the single biggest source of bookkeeping errors. A separate account makes quarterly reconciliation significantly faster — and most accounting platforms connect directly via open banking, pulling transactions automatically.
Not all platforms treat CIS deductions the same way. Before committing, verify that the software can: record the gross invoice value, log the CIS deduction separately, and carry that deduction forward as a credit against your tax liability. This is the detail that matters most for subcontractors specifically.
The One Genuine Benefit Worth Having
MTD is often framed as an HMRC demand — more admin, more deadlines, more compliance. That framing misses the point. The quarterly update process forces something most subcontractors have never had: a live, accurate picture of what they owe throughout the year.
For CIS trades where income fluctuates month to month — a quiet winter, a busy summer, a big materials bill in March — knowing your tax position in real time changes how you manage cash. You stop being surprised in January. You stop holding onto money "just in case." You know the number, you set it aside, and the rest is yours to use.
The subcontractors who will struggle with MTD are those who do nothing until the first deadline arrives. The ones who set up their software now, photograph this week's receipts, and reconcile once a month will find January 2027 significantly less painful than January 2026 was.
Not sure if MTD applies to you yet?
Check your gross turnover from last year, choose your software, and get set up before the first quarterly deadline. If you're not sure where to start, a CIS-specialist accountant can assess your position and recommend the right platform for your trade.
Get an MTD Readiness Review →Frequently Asked Questions
Making Tax Digital · CIS Subcontractors · 2026
Does Making Tax Digital apply to CIS subcontractors?
Yes. MTD for Income Tax Self Assessment applies to sole traders — which includes most CIS subcontractors — whose gross income from self-employment and/or property exceeds the threshold. From 6 April 2026, the threshold is £50,000 gross. It drops to £30,000 from April 2027 and is planned to fall further to £20,000 from April 2028. The threshold is based on gross turnover — the total on your invoices — not profit, and not what you received after CIS deductions.
What software do I need for Making Tax Digital?
You need HMRC-recognised software that connects directly to HMRC via API. The main options are full cloud accounting platforms (Xero, QuickBooks, FreeAgent, Sage) or bridging software that connects an existing spreadsheet to HMRC. A standard Excel or Google Sheets file without bridging software does not comply. For CIS subcontractors, a full accounting platform is usually the better choice because it can track CIS deductions on invoices automatically — bridging software requires you to manage that manually.
What happens if I miss an MTD quarterly update deadline?
HMRC operates a points-based penalty system for MTD. Each missed quarterly submission earns one penalty point. Once you accumulate enough points (4 points for quarterly filers), a £200 fixed penalty applies. Further £200 penalties apply for each subsequent missed submission while at the threshold. Points expire after 24 months of full compliance. Unlike the old Self Assessment late-filing penalty, there is no single annual fine — the system penalises repeated non-compliance rather than isolated lateness.
How does MTD interact with my CIS deductions?
Your CIS deductions — the amounts your contractors deduct from payments at source — are treated as advance payments toward your Income Tax liability. Under MTD, these need to be recorded accurately throughout the year so that your quarterly updates reflect the correct net position. The best MTD-compatible software for CIS subcontractors will allow you to record the gross invoice value, the CIS deduction separately, and carry those deductions forward as credits. This is worth checking specifically before you choose a platform, as not all software handles CIS as a standard feature.
I'm below £50,000 this year — do I need to do anything now?
You are not legally required to comply until your gross income crosses the relevant threshold. However, setting up MTD-compatible software now has two practical benefits. First, if your income grows — which is the goal — you will cross the threshold at some point and being already set up avoids a last-minute scramble. Second, the digital record-keeping habits MTD requires (photographing receipts, reconciling monthly, separating business finances) will make your current Self Assessment more accurate and your expense claims more complete. There is no downside to starting early.