Use gross figures before materials, van costs, tools, or Gas Safe fees are deducted.
If you're a self-employed Gas Safe registered engineer or heating installer, whether doing domestic boiler swaps, commercial contracts, or general plumbing and heating work, Making Tax Digital applies to you the same way it applies to any sole trader. Gas and heating work commands some of the highest day rates in the trades, which means the £50,000 threshold arrives sooner than many engineers expect.
Yes, if your gross trade income, plus any other self-employment income, exceeds the relevant threshold:
| Tax Year Assessed | Threshold | MTD Start Date |
|---|---|---|
| 2024–25 | Over £50,000 | 6 April 2026. Live since April 2026 |
| 2025–26 | Over £30,000 | 6 April 2027 |
| 2026–27 | Over £20,000 | 6 April 2028 |
Your gross income is your total invoiced amount before expenses, materials, van running costs, tools and Gas Safe fees are all deducted afterwards, not before, when checking your threshold.
| Expense Category | Examples |
|---|---|
| Materials | Boilers, parts, pipework, fittings bought for jobs |
| Registration | Gas Safe Register annual fee |
| Vehicle costs | Van running costs or mileage, at the current HMRC rate |
| Tools and equipment | Hand tools, testing equipment, via capital allowances for larger items |
| Insurance | Public liability and professional indemnity cover |
Dean's £74,500 gross income is well above the £50,000 Phase 1 threshold, MTD already applies to him, even though a large share of that figure is boiler and parts costs he'll claim back as expenses.
Yes, initially. If you invoice a single supply-and-fit price, the full amount, including the boiler's cost, counts as your gross trading income. The boiler's cost is then claimed back as a materials expense, reducing your taxable profit, but not your MTD threshold check, which uses the gross figure.
The same as any self-employed sole trader: over £50,000 gross income in 2024–25 means MTD from April 2026, over £30,000 in 2025–26 means April 2027, over £20,000 in 2026–27 means April 2028.
Yes, your Gas Safe Register annual fee is a standard allowable business expense, along with any other trade body memberships required for your work.
No, both are simply combined into one gross trading income total for your MTD threshold check, there's no separate treatment for domestic versus commercial work.
Any HMRC-recognised MTD software works. The main practical need is recording materials costs against each job accurately, which most trade-focused invoicing and accounting apps handle well.
Our free calculator checks your exact threshold, deadlines, and recommends the easiest software for your record-keeping.
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