Cash in hand does not mean tax-free. All income in the UK is taxable regardless of how it is paid. HMRC actively looks for undeclared cash earnings and has sophisticated tools to find it. Here is what you need to know about cash work and tax in 2026/27.
The Basic Rule
Income is taxable in the UK when you receive it — regardless of the payment method. There is no legal distinction between:
- A bank transfer for work done
- A cheque for services provided
- Cash handed over at the end of a job
All three are income. All three must be declared if they exceed your tax-free thresholds.
When Cash Income Does Not Need to Be Declared
The trading allowance of £1,000 per tax year applies to cash work just as it does to any other self-employed income. If your total cash (and other) trading income in 2026/27 is £1,000 or less, you do not need to declare it or register for Self Assessment.
Examples that fall under the allowance:
- Occasional odd jobs for neighbours (gardening, painting, odd jobs) totalling under £1,000
- One-off services such as helping someone move house for £300
- Selling homemade items at a market for £600
If your total trading income in the year exceeds £1,000, you must register for Self Assessment and declare all of it — not just the excess.
When You Must Declare Cash Income
| Situation | Must declare? |
|---|---|
| Cash earnings over £1,000/year from side work | Yes — register Self Assessment |
| Cash wages from an employer (regular job) | Yes — employer should deduct PAYE; if not, you still owe the tax |
| Cash tips from customers (direct) | Yes — tips are income |
| Cash from renting a room (over £7,500/year) | Yes — above Rent a Room threshold |
| Cash from selling personal items (not trading) | Generally no — but see below |
| Cash from trading (buying to resell) | Yes — trading income |
Selling Personal Items vs Trading
Selling things you own for personal use is generally not taxable — this is a capital disposal, not trading income. Selling an old sofa for £200 is not income.
However, HMRC will look at whether you are trading — buying items to resell at a profit, or regularly selling large volumes. HMRC’s guidance uses a set of “badges of trade” to assess this:
- Frequency of transactions
- Whether the asset was modified or improved before sale
- Whether you financed the purchase
- Whether the asset was sold at a profit
- The volume sold
If the activity looks like a business, it is taxed as one — regardless of whether payments were in cash or through an online platform.
How HMRC Finds Undeclared Cash
HMRC’s Connect system analyses data from over 100 sources, including:
- Bank account deposit patterns (large, regular unexplained cash deposits)
- DVLA (vehicles purchased that appear inconsistent with declared income)
- Land Registry (property purchases that appear inconsistent with declared income)
- Online marketplaces (eBay, Etsy, Amazon — platforms report seller data to HMRC)
- Anonymous reports from customers, competitors, and ex-employees
- Social media (lifestyle indicators vs declared income)
Connect cross-references all of this and flags anomalies for investigation. A painter and decorator declaring £15,000 income but depositing £40,000 per year is a clear flag.
Worked Example: Tom the Plumber
Tom works for a plumbing firm as an employee (PAYE, £28,000/year) and does weekend cash jobs for friends and family. In 2025/26, his cash work earned him £6,400.
- Trading allowance: £1,000
- Taxable self-employment profit: £6,400 − £1,000 = £5,400
- Income tax at 20%: £1,080
- Class 4 NI at 6%: £324 (on £5,400 above the £12,570 threshold — but his PAYE salary has already used the threshold, so this applies in full)
- Total additional tax and NI: approximately £1,400
Tom must register for Self Assessment, file a return for 2025/26, and pay this by 31 January 2027.
If Tom has not declared cash income for several years, he should make a voluntary disclosure. HMRC can look back 4–20 years depending on the circumstances.
What to Do If You Have Undeclared Cash Income
- Gather records — estimate your earnings for each year as accurately as possible
- Make a voluntary disclosure to HMRC — call 0300 200 3310 or use HMRC’s online disclosure facility
- Pay the tax owed plus interest — interest runs at 7.75% per annum from when the tax was due
- Receive reduced penalties — unprompted disclosure typically reduces penalties significantly, often to 0% for careless omissions
Coming forward voluntarily is always better than waiting for HMRC to find the income. HMRC offers significantly more favourable terms to those who disclose unprompted.
See our trading allowance guide, Self Assessment guide, and what happens if HMRC investigates me.