Contractor Invoice Generator

Create professional invoices with VAT breakdown, payment terms, and line items. Free to generate and view. Upgrade for unlimited invoices, PDF download and recurring templates.

Sending a proper invoice is step one of getting paid on time. If you freelance or contract in the UK, your invoice needs to include your business name, address, VAT number (if registered), a unique invoice number, payment terms, and a clear breakdown of services rendered. Missing any of these gives clients an excuse to delay payment.

The Federation of Small Businesses reports that UK SMEs are owed £23.4 billion in late payments at any given time. A professional, well-structured invoice reduces disputes and speeds up processing through your client’s accounts payable system. This generator creates compliant invoices with proper VAT calculations automatically.

Fill in your details once, add line items for each piece of work, and the tool produces a formatted invoice ready to send. The free version covers basic invoicing, while the paid tier adds PDF export, recurring templates, and a payment tracking dashboard.

How it works

  1. Enter your business details, client details, and payment terms.
  2. Add line items with descriptions, quantities, rates, and VAT treatment.
  3. Generate a formatted invoice with automatic VAT calculation and totals.

Written by the CalcStack team · Last updated April 2026

Your details

Client details

Invoice details

Line items

Description

Qty

Rate (£)

VAT

Frequently asked questions

What must a UK contractor invoice include?▾
A valid UK invoice must include: your business name and address, the client's name and address, a unique invoice number, the invoice date, a description of services, the amount charged, VAT details (if VAT registered), and your payment terms. Bank details for payment should also be included.
Do I need to charge VAT on my invoices?▾
You must charge VAT if your business is VAT registered. You must register for VAT if your taxable turnover exceeds £85,000 in a rolling 12-month period. If you are not VAT registered, you must not show VAT on your invoices.
What are standard payment terms for contractors?▾
Common payment terms are 14 or 30 days from invoice date. Some contracts specify 7 days for urgent work. The Late Payment of Commercial Debts Act allows you to charge interest and compensation if invoices are not paid on time.
What is the difference between a timesheet and an invoice?▾
A timesheet records hours worked and is typically approved by the client before invoicing. An invoice is a formal request for payment that references the approved timesheet. Many agencies and end clients require approved timesheets before they will process invoices.
Should I include my company number on invoices?▾
If you operate through a limited company, you are legally required to show your company registration number, registered office address, and place of registration (e.g. England and Wales) on all business documents including invoices.
What VAT rate should I charge for construction work?▾
Most construction services are subject to 20% standard rate VAT. However, the 5% reduced rate applies to certain works such as residential renovations of dwellings empty for 2+ years, conversions, and energy-saving materials. New build residential properties are zero-rated (0%).
What is the CIS deduction on contractor invoices?▾
Under the Construction Industry Scheme (CIS), main contractors must deduct 20% (or 30% for unverified subcontractors) from payments for labour. The deduction does not apply to materials. CIS deductions should be clearly shown on the invoice.
How long should I keep copies of invoices?▾
HMRC requires you to keep records of all invoices for at least 6 years. If you are VAT registered, you must keep VAT invoices for 6 years. It is good practice to store both digital and physical copies in a systematic filing system.
Can I invoice without a limited company?▾
Yes. Sole traders and partnerships can issue invoices. As a sole trader, you use your own name or trading name. You do not need a company registration number, but you must include your name and address on the invoice.
What happens if my invoice is not paid on time?▾
Under the Late Payment of Commercial Debts Act 1998, you can charge statutory interest at 8% plus the Bank of England base rate, plus a fixed compensation of £40-£100 depending on the debt amount. Always issue a formal reminder before escalating.

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© 2026 CalcStack — a Flavoureak UK Ltd product. This invoice generator is provided as a convenience tool. It is your responsibility to ensure invoices comply with HMRC requirements. This is not accounting advice.