How to Invoice Clients
A practical, no-nonsense guide to invoicing clients professionally — from what to include, to what to do when they don't pay on time.
Start invoicing with UsemintyThe 7-step invoicing process
Follow these steps consistently and you'll get paid faster and have fewer disputes.
Agree on the scope and price before you start
The best invoicing starts before the invoice is written. Agree in writing — even by email — on exactly what deliverables are included, the total price or hourly rate, and the payment terms. A clear agreement prevents the most common disputes.
Create the invoice with all required details
Your invoice must include: your business name and address, the client's legal name and address, a unique invoice number, the issue date and due date, an itemised list of services, any applicable VAT, the total amount due, and your payment details.
Set clear payment terms
Net 14 is standard for freelancers (payment within 14 days of the invoice date). Net 30 suits larger corporate clients. Always state the due date explicitly — 'due within 30 days' leaves room for misinterpretation, while '15 May 2025' does not.
Send the invoice promptly
Send the invoice the same day you complete the work, or on the agreed billing date for ongoing contracts. Delayed invoicing signals to clients that payment is not urgent to you — which often means they treat it as non-urgent too.
Follow up before the due date
A brief, friendly confirmation email 2-3 days before the due date reduces late payments significantly. Something as simple as 'Just a reminder that invoice INV-045 for €2,400 is due on 15 May — please let me know if you need anything' is enough.
Chase overdue payments professionally
If payment is 1 day late, send a polite reminder. At 7 days, follow up again and mention that you may charge a late payment fee if applicable. At 30 days overdue, consider a formal letter before action or involving a debt recovery service.
Mark paid invoices and keep records
Once payment arrives, mark the invoice as Paid in your invoicing system and record the payment date. Good records protect you in case of disputes or tax audits and make preparing your annual accounts far easier.
Understanding payment terms
Choose the right payment terms for each client relationship and project type.
| Term | What it means |
|---|---|
| Net 14 | Payment due within 14 days of the invoice date. Common for freelancers and small projects. |
| Net 30 | Payment due within 30 days. Standard in corporate environments. |
| Due on receipt | Payment expected immediately. Suitable for small one-off jobs or trusted long-term clients. |
| 50% upfront | Half the total is paid before work begins. Protects you on large or risky projects. |
| Milestone-based | Payment is split across project milestones. Useful for long-running projects. |
Frequently asked questions
When should you send an invoice to a client?
Send the invoice on the day you deliver the work, or on the agreed billing date for monthly retainers. The earlier you invoice, the earlier the clock starts on your payment terms.
What is the best way to send an invoice to a client?
Email a PDF invoice directly to the accounts payable contact, not just your day-to-day contact. Use a clear subject line: 'Invoice INV-045 — [Your Name] — Due 15 May 2025'. Attach the PDF and include the key details in the email body so they can act without opening the attachment.
What do you do if a client doesn't pay?
Start with a polite email reminder the day after the due date. Follow up again at 7 days. At 14-30 days, consider a formal demand letter. For larger amounts, you may involve a solicitor or debt recovery agency. In many countries you are entitled to charge statutory interest on late payments.
Can you charge late payment fees on overdue invoices?
Yes, in most countries — but only if you stated the late fee clearly in your original agreement or on the invoice. A common structure is a fixed fee plus statutory interest (e.g. 8% above base rate in the UK). Check the rules in your jurisdiction.
Do you need a contract to invoice a client?
You can invoice without a formal contract, but it leaves you vulnerable. At minimum, have a written agreement (even by email) confirming the scope, price, and payment terms before work begins.
How do you invoice an international client?
Invoice in the currency specified in your agreement (or the client's preferred currency). Include your IBAN and SWIFT/BIC codes for international bank transfers. Note any applicable VAT rules — in the EU, B2B services to foreign clients are often zero-rated under the reverse charge mechanism.
What's the difference between an invoice and a receipt?
An invoice is a request for payment, sent before or when the work is complete. A receipt is proof that payment was received. Once a client pays your invoice, you can issue a receipt — though in practice many freelancers simply mark the invoice as 'Paid' and treat that as sufficient.
Related guides
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