What Should an Invoice Include UK? Complete Checklist
Everything your UK invoice must include to be legal, professional, and effective at getting you paid.
Whether you're a sole trader, freelancer, or small business owner, knowing what to include on your invoices is crucial. This guide covers UK-specific legal requirements and best practices that help you get paid faster.
Legal Requirements: What HMRC Demands
Under UK law, all invoices must contain specific information. Missing these details can cause payment delays or tax compliance issues.
Essential Invoice Elements
1. Unique Invoice Number
Required by law. Must be sequential and never reused. Example: INV-000001, INV-000002, etc.
2. Your Business Details
Full legal name (as registered with HMRC) and your business address.
3. Client Details
Client's full name or company name and address.
4. Invoice Date
The date you're issuing the invoice. This starts the payment term countdown.
5. Description of Work
Clear description of goods or services provided. Be specific to avoid disputes.
6. Amount Charged
Total amount due. If VAT registered, show VAT separately.
7. Payment Terms
When payment is due (e.g., "Payment due within 14 days" or a specific date).
Additional Requirements for VAT-Registered Businesses
If your business is VAT registered, including voluntary registration, check the VAT invoice requirements for your supply. A full VAT invoice includes:
- ✓ Your VAT registration number
- ✓ The VAT rate charged (usually 20%)
- ✓ The total amount excluding VAT
- ✓ The VAT amount
- ✓ The total amount including VAT
What is a simplified VAT invoice?
It is a less detailed VAT invoice for qualifying supplies of £250 or less. Your customer must agree; a Northern Ireland business cannot use this option for a customer in an EU member state.
Include your business name, address and VAT number, the tax point, a description of the supply, and the VAT-inclusive amount and rate for each applicable rate. Check HMRC VAT Notice 700, section 16.6 for the conditions.
This is not the same as an ordinary non-VAT invoice. Experi uses its normal invoice workflow; there is no separate simplified-VAT mode. Review the required fields before issuing.
Read the full simplified-VAT guide and worked example.
See how to print an invoice in Experi →Optional But Highly Recommended
While not legally required, these elements make your invoices more professional and effective:
📧 Contact Information
Email, phone number, and website. Makes it easy for clients to reach you with questions.
💳 Payment Instructions
Bank details, PayPal address, or payment link. The easier you make it to pay, the faster you get paid.
🏢 Company Registration
Add applicable company and VAT registration details. Do not put your personal UTR or National Insurance number on customer invoices.
📝 Purchase Order Number
If your client provided a PO number, include it. Essential for corporate clients' accounting systems.
📅 Due Date
Specific date when payment is due. Clearer than "within 14 days" and reduces confusion.
⚖️ Terms & Conditions
Late payment charges, dispute resolution, or cancellation policy. Protects you legally.
Detailed Breakdown: Line Items
For services or multiple products, break down charges into line items. Each should show:
- • Description - What was provided
- • Quantity - How many hours/units
- • Unit price - Rate per hour/item
- • Line total - Quantity × Unit price
Example: "Website Design - Homepage - 8 hours @ £50/hour = £400"
What About Discounts?
If you're offering a discount, show it clearly:
Subtotal: £500.00
Discount (10%): -£50.00
Total: £450.00
For VAT-registered businesses, apply discounts before calculating VAT.
Common Invoice Mistakes to Avoid
- ❌ Vague descriptions - "Services rendered" doesn't explain what you did
- ❌ Missing payment terms - Clients will assume 30+ days
- ❌ No bank details - Makes it harder to pay you
- ❌ Inconsistent numbering - Skipping numbers looks unprofessional
- ❌ Wrong VAT calculations - Can result in HMRC penalties
Sample Invoice Layout
Here's what a complete UK invoice should look like:
Your Business Name
123 Business Street
London, SW1A 1AA
hello@yourbusiness.com
INVOICE
INV-000123
21 January 2026
Bill To:
Client Company Ltd
456 Client Avenue
Manchester, M1 1AA
| Description | Qty | Rate | Amount |
|---|---|---|---|
| Website Development | 40 | £50.00 | £2,000.00 |
Subtotal: £2,000.00
VAT (20%): £400.00
Total: £2,400.00
Payment Terms:
Payment due within 14 days (by 4 February 2026)
Bank: YourBank | Sort: 12-34-56 | Account: 12345678
The Easy Way: Professional Invoicing Software
Creating invoices manually means remembering all these elements every time. Professional invoicing software automatically includes everything required and looks polished.
Experi: All Required Elements, Automatically
Never miss a required field again. Experi's UK-compliant templates include everything legally required, plus professional touches that get you paid faster.
- ✓ Automatic sequential numbering
- ✓ Pre-filled business details
- ✓ VAT calculations built-in
- ✓ Professional PDF generation
- ✓ Email delivery with tracking
Multi-Currency Support
Invoice international clients in 20 currencies, including GBP, USD and EUR
Key Takeaways
- ✓ Always include: unique number, dates, both parties' details, description, amount, payment terms
- ✓ VAT-registered businesses need additional VAT information
- ✓ Add contact details and payment instructions for faster payment
- ✓ Use clear line items for multi-item invoices
- ✓ Keep all invoices for at least 5 years (HMRC requirement)
Stop worrying about what to include
Experi handles all the details automatically. Focus on your work, not invoice templates.
Create Professional Invoices Free