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 (turnover over £90,000), your invoices must also include:

✓ Your VAT registration number
✓ The VAT rate charged (usually 20%)
✓ The total amount excluding VAT
✓ The VAT amount
✓ The total amount including VAT

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

Company number, VAT number (if registered), or sole trader UTR. Builds trust with clients.

📝 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

Try Free - Create Your First Invoice

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)

What Should an Invoice Include UK? Complete Checklist