How to deal with unpaid invoices and avoid late payments

Published Monday 30 March 2026

Table of contents

• What is an unpaid invoice?
• Common reasons why invoices go unpaid
• How do unpaid invoices affect your business?
• How to chase late payments
• Your legal rights with unpaid invoices
• When you still don't receive payment
• Tips for avoiding late payments
• Streamline your invoicing with Xero
• FAQs on unpaid invoices

Key takeaways

• Send payment request letters immediately when invoices become overdue to clarify whether delays are intentional or accidental, as prompt action prevents compounding delays and maintains professional relationships.
• Implement upfront payment policies by requesting deposits or partial payments before starting work to reduce financial risk and improve cash flow while screening for potential payment problems.
• Use phone calls rather than emails when chasing unpaid invoices, as direct conversation makes it harder for clients to ignore you and allows for real-time negotiation of payment dates.
• Stop all work immediately if clients aren't paying or responding to messages, as protecting your cash flow takes priority over preserving relationships that put your business at risk.

What is an unpaid invoice?

An unpaid invoice is a bill for goods or services that hasn't been paid by the due date. It's also called an overdue invoice or past due invoice once the payment deadline passes.

Unpaid invoices are common in business, but they create real problems when they pile up or drag on too long. Understanding how to manage them protects your cash flow and keeps your business running smoothly.

Common reasons why invoices go unpaid

Understanding why clients don't pay helps you choose the right response. Most unpaid invoices fall into one of these categories:

• Cash-flow problems: The client wants to pay but doesn't have the funds right now.
• Administrative errors: The invoice was lost, sent to the wrong person, or filed incorrectly.
• Disputes: The client disagrees with the amount, the work delivered, or the terms.
• Disorganisation: The client simply forgot or lacks a system for tracking payments.
• Intentional non-payment: The client has no intention of paying.

Your approach should match the cause. A forgotten invoice needs a gentle reminder. A disputed amount needs a conversation. Intentional non-payment may require escalation.

How do unpaid invoices affect your business?

Unpaid invoices directly hurt your cash flow. When payments arrive late or not at all, you may struggle to cover operating costs, pay suppliers, or plan for growth.

Occasional late payments happen to most businesses. But when they become frequent or drag on too long, the effects compound quickly.

Unpaid invoices can trigger a chain reaction across your business:

• Supplier relationships: If you can't collect payment, you may not be able to pay your own suppliers on time.
• Credit rating: Missed payments to vendors can damage your business credit score, as scoring models like PAYDEX directly associate lower scores with a high risk of late payment.
• Professional reputation: Clients and partners may question your reliability if cash-flow problems become visible.
• Future opportunities: Strained relationships can make it harder to win new work or negotiate favourable terms.

Successfully invoicing and managing unpaid invoices is crucial to sustain your business's long-term financial health.

How to chase late payments

Here are proven steps to recover overdue payments:

1. Write a payment request letter or email
2. Send an overdue invoice
3. Send a statement of accounts
4. Make the phone call and prepare to negotiate
5. Charge a late payment fee
6. Cut them off until outstanding invoices are paid
7. Hire a debt collector
8. Call in the lawyers

Write a payment request letter or email

A payment request letter is a polite, professional reminder sent when an invoice becomes overdue. In most cases, this simple step prompts customers to pay without further follow-up.

Send your first request as soon as you notice the payment is late. If the delay turns out to be intentional, this letter also creates a paper trail for any escalation you may need later.

Acting quickly matters for three reasons:

• Avoid compounding delays: The longer you wait, the harder it becomes to collect.
• Clarify intent: A prompt reminder helps you determine whether the delay was an oversight or intentional.
• Protect the relationship: Professional communication keeps the door open for future work.

Structure your payment request letter to be brief, professional, and specific. Include these elements:

1. Open with a standard greeting
2. Reference the unpaid invoice by number, due date, and amount owed
3. Ask when you can expect payment
4. Include a brief reminder of your payment terms

Keep it short. You don't need to describe the work or services again as those details are already on the original invoice.

Send an overdue invoice

An overdue invoice is your original invoice marked with an "overdue" stamp to signal urgency. Send one when your initial payment request goes unanswered.

Attach the stamped invoice to a follow-up email as a formal reminder. The visual cue reinforces that payment is now past due and requires immediate attention.

Set up an invoice reminder schedule as part of your regular accounting routine. This keeps follow-ups consistent and ensures customers stay aware of what they owe.

You can manage reminders manually or use automatedinvoicing software to send them on your behalf until payment arrives.

Send a statement of accounts

A statement of accounts summarises all outstanding invoices for a single client in one document. Use it when you have multiple unpaid invoices with the same customer.

This approach won't reduce your overdue invoices on its own, but it streamlines your admin by consolidating multiple follow-ups into one communication. Accounting software can generate these statements automatically.

Follow up with a phone call to make sure your client received and reviewed the statement.

Make the phone call and prepare to negotiate

Phone calls get better results than emails when chasing unpaid invoices. It's much harder for a client to ignore you when you're speaking directly.

Keep the conversation focused and productive by following this structure:

1. Greet the client, then reference the specific unpaid invoices by number or date
2. Ask when you can expect payment
3. Wait for their response, even if there's an awkward pause, to encourage them to commit to a date
4. End the call only after they've provided a payment date

Be prepared to negotiate. If the unpaid amount is small and the client can pay soon, you might agree to extend the deadline while pausing any new work until they've paid.

If you're uncomfortable handling these conversations yourself, ask your bookkeeper or accountant to follow up on your behalf. They can often approach the situation with professional distance that makes negotiation easier.

Charge a late payment fee

A late payment fee is an additional charge added to invoices that remain unpaid past the due date. It creates a financial incentive for clients to pay on time.

Include your late-fee policy in your payment terms before starting any work. Make the fee easy to understand by using a flat amount rather than a percentage.

For example:

• Due by 1 June: £100
• Due after 1 June: £110

Simple, predictable fees motivate customers to pay on time. When a payment becomes overdue, notify the client that the late fee now applies.

Goodwill tip: Offer to waive the fee if they pay within 48 hours. This encourages quick action while preserving the relationship.

Cut them off until outstanding invoices are paid

Stop work immediately if a client isn't paying or responding to your messages. Continuing to deliver services without payment puts your own business at risk.

Notify the client clearly: no further work until all outstanding invoices are paid in full. You may lose the client, but protecting your cash flow takes priority over preserving a relationship that isn't working.

Hire a debt collector

A debt collection service recovers unpaid invoices on your behalf when a customer stops cooperating. It's typically a final step after other collection methods have failed.

Using a debt collector may strain the client relationship, but it can be effective when direct communication has broken down.

Key cost considerations:

• Typical fees: 5%–25% of the amount recovered.
• Cost recovery: Under UK law, you can often pass collection costs onto the debtor.

You can find debt collection service providers through professional industry bodies or trade associations.

Call in the lawyers

Legal action is a last resort when debt collection fails. Consult a lawyer who specialises in debt recovery before proceeding.

The right approach depends on the debtor's business structure:

• Sole traders and partnerships: Personal liability may apply.
• Companies: Recovery options differ based on company status.
• Small claims court: A lower-cost option for smaller amounts.

Your debt collector may have in-house legal expertise or can refer you to a specialist. Ask before engaging separate legal counsel.

Your legal rights with unpaid invoices

When a client refuses to pay, you have legal options, but time limits apply. Understanding your rights helps you decide when and how to take further action.

In many places, there is a time limit for pursuing an unpaid invoice in court; for example, most US jurisdictions have statutes of limitations between three and six years for debts. After this period, you may lose your right to recover the debt. Before taking any legal steps, document all your communication and keep copies of the original invoice and contract.

Consulting a lawyer or debt recovery specialist can help you understand the best approach.

When you still don't receive payment

There are plenty of ways to deal with overdue invoices, but sometimes they simply don't work. Consider these options:

Write off the unpaid invoice

Writing off an unpaid invoice removes it from your accounts receivable and adjusts your tax liability, but the accounting standards for doing so can be complex for small and medium enterprises (SMEs) to apply. This step matters most if you use accrual-based accounting, where you report income when invoiced rather than when received.

If you've already paid tax on income you never collected, writing off the invoice lets you claim that tax back.

To write off an invoice as a bad debt:

• Gather evidence: Keep correspondence showing your collection attempts.
• Prove non-payment: Document that the debt is genuinely uncollectable.
• Update your records: Use accounting software like Xero to track and record the write-off.

Cash-based accounting simplifies this process. Since you only record income when payment arrives using the cash method of accounting, you don't need to write off unpaid invoices. Just exclude the amount from your income statements.

Perform credit checks on prospective clients

Credit checks reveal a prospective client's payment history before you agree to work together. They show whether someone pays bills on time and honours their debts.

Run a credit check before taking on new clients, especially for large projects. You can buy business credit reports from various services. A positive score suggests they'll pay promptly with minimal follow-up. A poor score is a warning sign worth considering before you commit.

Tips for avoiding late payments

Prevention is more effective than collection. The following strategies help you get paid on time and reduce the need for follow-up.

Set time aside to track outstanding invoices

Schedule regular time each week to review your accounts receivable. Spotting overdue invoices early lets you send reminders promptly, which speeds up payment and strengthens client relationships.

Take partial payment upfront

Upfront payments reduce your risk and improve cash flow. Request a deposit or percentage of the total fee before starting work.

Benefits of taking partial payment upfront:

• Risk reduction: Confirms the client intends to pay.
• Cost coverage: Offsets your expenses for materials or time.
• Cash-flow improvement: Money arrives earlier instead of all at once at project end.
• Client screening: Reluctance to pay upfront can signal future payment problems, as many business owners rely on a mix of personal and business credit, meaning their personal financial stability is often at stake.

Offer payment plans to clients

Payment plans let clients pay in instalments rather than all at once. They work well for large projects or when a client faces temporary cash flow challenges.

Proactive payment plans tie payments to project milestones:

• 25% upfront
• 25% at the midpoint
• 50% on completion

Reactive payment plans help recover overdue amounts by splitting the total into manageable monthly payments.

Both approaches strengthen client relationships, improve your cash flow, and reduce the risk of invoices going unpaid.

Use accounting software like Xero

Automated invoicing saves time and reduces late payments. Xero sends invoices and reminder emails on your behalf, prompting customers to pay without manual follow-up.

This removes the stress of chasing payments and frees you to focus on running your business instead of managing admin.

Streamline your invoicing with Xero

Chasing unpaid invoices takes time away from running your business. Xero's automated invoicing handles the follow-up for you, sending reminders and tracking payments so you only step in when it's truly necessary.

With Xero, you can:

• Automate payment reminders: Send follow-ups without lifting a finger.
• Track outstanding invoices: See what's due and what's overdue at a glance.
• Integrate with your accounting: Keep invoicing and bookkeeping in one place.

Get one month free and see how much easier invoice management can be.

FAQs on unpaid invoices

Find answers to common questions about managing unpaid invoices.

What is an unpaid invoice?

An unpaid invoice is a bill for goods or services that remains outstanding after the payment due date. Once the deadline passes, it becomes an overdue or past due invoice.

How long can an invoice legally go unpaid?

The time limit for taking legal action over an unpaid invoice varies by location. In the UK, for example, you generally have up to six years, but actions like a partial payment can restart the time period in some jurisdictions. Check the rules for your region.

What's the difference between an outstanding invoice and an overdue invoice?

Outstanding invoices include all unpaid invoices, whether or not the due date has passed. Overdue invoices (also called past due invoices) are a subset that have passed their payment deadline and require immediate follow-up.

Should I charge interest on late payments?

You can charge interest on late payments if this is stated in your payment terms. Some regions also have laws that allow you to charge statutory interest on late commercial payments, even if it's not in your contract.

Can I refuse to work with a client who has unpaid invoices?

Yes, you can pause or stop working with a client who has not paid for previous work. It's a necessary step to protect your business from further financial risk.