If you're a VAT-registered electrician, plumber, or contractor, your invoice isn't just a bill, it's a legal document. Get the format wrong and you risk a client refusing to pay, or worse, a headache when your accountant reconciles your return. Here's what actually needs to be on it, and where tradespeople most often go wrong.
Do you need to charge VAT at all?
You only charge VAT if you're VAT-registered, either because your taxable turnover crossed the registration threshold in your country, or because you registered voluntarily. If you're not registered, don't add a VAT line, and don't call your document a "VAT invoice." A regular invoice is fine.
If you are registered, VAT isn't optional on qualifying work: you must charge it, show it separately, and remit it, regardless of whether the client is a homeowner or a business.
What a compliant VAT invoice needs
At minimum, a VAT invoice should include:
- A unique, sequential invoice number
- Your business name, address, and VAT registration number
- The client's name and address
- The invoice date and the date the work was completed (the "tax point")
- A description of the work or materials supplied
- The rate of VAT applied to each line (standard, reduced, or zero-rated)
- The net amount, the VAT amount, and the gross total
Miss the VAT number or the tax point and the invoice technically isn't valid, even if the client pays it anyway.
Common mistakes that trigger questions
Mixing VAT rates without splitting them out. If a job includes both standard-rated labour and zero-rated materials (common in some new-build or accessibility work), lump them into one line and you've made the invoice impossible to audit.
Rounding at the wrong step. Round the VAT per line, not on the invoice total, small jobs with many lines can drift by a few cents and cause reconciliation mismatches.
Reusing invoice numbers. Sequential numbering isn't a suggestion, gaps or duplicates are one of the first things flagged in a review.
Forgetting the tax point on deposits. If you take a deposit before finishing a job, the tax point is usually the date you received the deposit, not the date you invoice the balance.
Quick check: if you can't point to the VAT number, the tax point, and a clean rate split on an invoice in under ten seconds, it's worth fixing the template before your next job.
Where invoicing software actually helps
The mistakes above are almost all data-entry mistakes, not calculation mistakes, so the fix is removing the manual re-typing. In Chargd, every invoice defaults to your saved business details and VAT number, line items carry their own tax rate so mixed-rate jobs stay split automatically, and numbering is sequential by default because you never touch it. When it's time to hand a quarter's invoices to your accountant, bulk export gives you clean CSVs instead of a folder of PDFs to re-key.
Key takeaways
- Only add a VAT line if you're actually VAT-registered.
- A valid VAT invoice needs your VAT number, a tax point, and rates split per line.
- Deposits have their own tax point, don't let software default that to the final invoice date.
- Sequential numbering and consistent rounding matter more than most tradespeople think.
Get the structure right once, in a template, and every invoice after that is correct by default, no more re-checking your own math before you hit send.
If you're still weighing which app to build that template in, see how Chargd compares to other Mac invoicing software without a subscription.
