How to send an invoice as a sole trader UK (with template)

A mate of mine went solo as a plumber last year. First proper job on his own, a full bathroom for a family down the road, went well, customer happy. Then he sat down that evening to send the invoice and realised he'd never actually made one. He fired off a text saying "that's £840 when you're ready" and left it at that. Took him six weeks and three awkward doorstep chats to get paid.

The work was never the problem. The invoice was. A proper invoice, sent the right way at the right time, is the difference between money in the bank on Friday and chasing a customer who's decided your text doesn't count.

This guide covers what a sole trader invoice legally needs, whether you add VAT, a worked example with real numbers, and how to send it so you actually get paid.

What a sole trader invoice legally needs

There's a common worry that invoicing as a sole trader involves some special registration or a magic number you don't have. It doesn't. A sole trader invoice is a plain document, and the legal must-haves are short.

Every invoice you send needs to show:

• The word "invoice" clearly on the document. Not "receipt", not "statement". This matters for your records and the customer's.
• A unique invoice number. Sequential is easiest: 001, 002, 003. Never repeat a number and never skip about randomly. If HMRC ever looks, a clean run of numbers shows nothing's been hidden.
• Your name and any trading name. As a sole trader you can invoice under your own name (Adam Wójcik) or a business name (Wójcik Plumbing). If you use a business name, put "Adam Wójcik trading as Wójcik Plumbing" so it's clear who the legal person behind it is.
• Your address and contact details. A real address and a phone number or email. This is a legal requirement, and it also makes it easy for the customer to query anything before they decide to sit on it.
• The customer's name and address. Bill the actual person or business responsible for paying.
• The date the invoice is issued, and the date the work was done or supplied if that's different.
• A clear description of the work. "Bathroom installation" is thin. "Supply and fit bathroom suite, first and second fix plumbing, 2 days labour" gives the customer nothing to argue about later.
• The amount due, broken down if it helps, with a clear total at the bottom.

That's the full legal picture for a non-VAT-registered sole trader. No company registration number, because sole traders aren't registered at Companies House. That number only exists for limited companies. If you've ever felt you were missing something because you don't have one, you're not. You're just a different legal structure.

Do you add VAT? The £90,000 question

This is where most of the confusion sits, so here's the plain version.

You only charge VAT if you're VAT registered. You only have to register once your VAT taxable turnover goes over the threshold, which is £90,000 in any rolling 12-month period as of 2026. That's not a calendar year, it's any 12 months on the trot, so you keep a running eye on it.

Most solo trades starting out are nowhere near £90,000, so they invoice without VAT, don't add a VAT line, and don't mention it at all. The total on the invoice is the total the customer pays. Simple.

Once you cross the threshold, or if you choose to register voluntarily, three things change on your invoices:

• You must show your VAT registration number from HMRC.
• You must show the VAT rate applied, usually 20% for most trade work, though some construction work is 5% or 0%.
• You must show the VAT amount as a separate line, then the gross total.

A worked example: invoicing a bathroom job

Let's run the numbers on a real job so you can see the shape of a finished invoice. Sole trader plumber, not VAT registered, fitted a bathroom over two days.

• Labour: 2 days at £220 per day = £440
• Materials: taps, waste, silicone, fixings, pipe and fittings = £180
• Supply and fit shower valve = £220
• Total due: £840

No VAT line, because he's under the threshold. Here's what that looks like written up properly.

Everything the customer needs to pay is on one page. Who it's from, who it's for, what the work was, what's owed, when it's due, and exactly how to pay it. No back and forth, no "can you send me your bank details", no reason to delay.

How to send it (and get paid faster)

Timing does more for your cashflow than any chase letter. The single biggest move you can make is this: send the invoice the same day the job finishes.

Not three days later when you're back on the sofa. Not the weekend when you finally sit down to the paperwork. The same day, ideally before you've left the customer's road.

There's a reason for it. The customer pays an invoice that lands while the job is still fresh, the new bathroom still smells of sealant, and they're still pleased with the result. Send it a week later and the goodwill has cooled. They've moved on, the money feels less urgent, and your invoice slides down the pile.

On the how, a few practical points:

• Send a PDF, not a photo of a handwritten note. A PDF looks like a business that's going to follow up. A scribbled text looks like something you can ignore. My mate's "£840 when you're ready" text is exactly the format that gets left for six weeks.
• Email it with a short, plain message. "Hi, invoice for the bathroom attached, all the details are on there. Any questions just give me a shout. Cheers, Adam." That's it.
• Put the bank details on the invoice, not in the email body. One place to look, no hunting.
• Keep your own copy. Save every invoice you send. HMRC asks sole traders to keep records for at least 5 years after the relevant 31 January self-assessment deadline, and you'll need the totals when you file.

Payment terms and bank details that get you paid

Two small things on the invoice do a lot of the work here.

First, the payment terms. The old default is 30 days, carried over from big-company accounts departments. For a solo trade doing domestic work, that's far too generous. Use 7 or 14 days. And write the actual date, not the jargon. "Payment due by 24 August 2026" is clearer than "net 14" and gives the customer nothing to be vague about.

Second, the bank details. Put your sort code, account number, account name, and a payment reference (the invoice number) right on the invoice. The easier you make it to pay in the moment they read it, the more of them do exactly that. Every extra step you leave in, like making them ask for your details, is another chance for the job to get parked.

If you want the option to charge interest on late payment down the line, that has to be in terms the customer agreed before the work started. For a homeowner, the Late Payment Act 1998 doesn't apply automatically, so a late-payment clause in your written terms is what gives you the right. For business customers it applies by law. Either way, get the invoice out first and get it out fast.

What NOT to do (the 5 common mistakes)

1. Don't invoice by text with a bare number. "£840 when you're ready" isn't an invoice, it's a suggestion. It has no due date, no reference, no detail, and it's the easiest thing in the world to ignore. Send a proper document.
2. Don't leave the invoice number off or reuse the same one. A clean sequential run keeps your records straight and keeps you covered at self-assessment. Duplicated or missing numbers cause confusion when you're reconciling who's paid.
3. Don't wait until the weekend to send it. Every day you delay pushes your payment date back by the same amount, and the customer's goodwill fades with it. Same day, every time.
4. Don't add VAT if you're not registered. Charging VAT when you're not registered for it is a real problem with HMRC, not a harmless rounding-up. If you're under the £90,000 threshold and haven't registered, there's no VAT line. Full stop.
5. Don't forget the due date and bank details. An invoice with no clear payment date and no way to pay is a to-do list item the customer will get to eventually. Spell out exactly when and exactly how, on the invoice itself.

The habit that keeps your cashflow healthy

Invoicing well as a sole trader isn't complicated. It's a plain document with the right details, sent the same day, with a clear due date and your bank details on it. Do that consistently and you'll be paid faster than most of the trade around you, not because you did anything clever, but because you didn't leave the door open for delay.

The one habit worth building from your very first solo job: raise and send the invoice before you've left the customer's road. TradeStash does it in about 30 seconds from the van, so the invoice lands before you've even loaded the tools back in. Same-day invoicing is the biggest single thing you can do for your cashflow, and it costs you nothing but the habit.