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Dealing with outstanding invoices can be a frustrating task for any business or organisation. However, with the right approach, you can effectively communicate the urgency of payment to your clients and customers.  

In this guide, we will walk you through writing an impactful late payment letter or email that will help you reclaim your rightful payment. From understanding the importance of prompt payment to crafting a persuasive message, we've got you covered. 

So, let's dive in and discover the secrets to getting paid on time.

Importance of addressing overdue invoices 

Late or unpaid invoices can have a significant negative impact on your business, particularly on your cash flow. Here are some key points to consider: 

  • Cash flow issues

When invoices go unpaid, businesses struggle to maintain a healthy cash flow. Cash flow is the movement of money in and out of your business, and it is crucial for covering expenses, paying suppliers, investing in growth opportunities, and meeting day-to-day operational costs. If your clients pay you late or do not pay you at all, it can hinder your ability to pay debts and operate your business efficiently. This can lead to difficulties in meeting financial obligations and may even affect your ability to secure future business loans. 

  • Stifled growth opportunities 

Lack of timely payment can limit a business's ability to invest in growth initiatives. Without a steady influx of cash, businesses may miss out on crucial opportunities to expand, innovate, or acquire new customers. This can hinder the long-term growth and success of your business. 

  • Strained supplier relationships 

When invoices go unpaid, it can strain relationships with suppliers. If you are unable to pay your suppliers on time, they may be less willing to extend credit terms or offer favorable pricing in the future. This can impact your ability to secure the necessary resources and materials to run your business effectively. 

  • Operational inefficiencies 

Late or unpaid invoices tie up valuable resources and can hinder the smooth operation of your business. Instead of focusing on growth and development, you may find yourself spending time and effort chasing payments and managing cash flow issues. This can divert your attention away from core business activities and lead to inefficiencies. 

What information should I include in an overdue invoice letter?  

An overdue or unpaid invoice letter serves as a formal communication to remind a client or customer that their payment is past due. The letter should be professional, yet friendly, and should clearly communicate the urgency of the situation while providing the necessary information for payment. 

When writing an overdue invoice letter, it is important to include key elements to ensure clarity and effectiveness. Here are the key elements to include: 

  • Invoice details: 

Include the invoice number and date to help the customer identify the specific invoice that is overdue. 

  • Amount owing:  

Clearly state the amount that is owed by the customer. 

  • Payment terms:  

Include information about any late fees or penalties associated with late payment. 

  • Reminders of previous letters:  

If you have sent previous reminders, briefly mention them to emphasize the importance of prompt payment. 

  • Instructions for payment:  

Provide clear instructions on how the customer can make the payment, including any links or references to payment platforms. 

  • Contact information:  

Include your contact information, such as your email address or phone number, so that the customer can easily reach out to you for any questions or concerns. 

It is also important to tailor the language of the letter to the specific situation. The tone should be professional, yet firm, and should clearly communicate the urgency of the situation.  

Remember to follow up with the customer at regular intervals, such as after a week or two, and at 30, 60, and 90 days after the due date, to ensure that the payment is made. Sending the letter on a Tuesday, either right before or after lunch, is considered to be the best time for email communication during the week. 

Overall, an effective overdue invoice letter should be clear, concise, and professional, while also conveying the importance of prompt payment and maintaining a positive business relationship with the customer. 

How to write a letter asking for an overdue payment   

Sending a reminder or overdue invoice letter involves several stages. Below, you'll find a breakdown of these stages, along with some examples of overdue payment letters for each stage: 

Unpaid overdue invoice letter: Polite reminder

There are different stages of sending a reminder or overdue invoice letter and this starts with a polite notice which should be sent out within the first 14 days after expected payment. It is also important that you keep a copy of this, and any future overdue payment reminder letter for your records, or send electronically, leaving a paper trail.

Polite Reminder

Subject line: [Your company name] – Overdue Payment – [Invoice number]

Dear [Name],

This is a polite reminder from [company name] that we have not yet received payment for:

[Invoice number, balance, due date]

As we are not aware of any outstanding issues or reasons for non-payment, we would ask that you confirm receipt of this reminder and advise us as to when to expect the payment.

Please see attached the invoice for reference. If you have any queries or need any assistance, please do let us know.

Kind regards,


Unpaid overdue invoice letter - Firm reminder (14 days)

Following this late payment letter, you should hopefully receive payment. It could be as simple as an oversight and the customer will recover the payment promptly. However if this isn’t the case, further attempts should be made to recover the payment and we suggest sending these electronically and via post to ensure your overdue invoice letter is received.

Upon 14 days of no payment, you should send a firm reminder for the overdue invoice. Within this unpaid invoices letter, you should put emphasis on the timeframe and reference your previous overdue payment reminder letter.

Unpaid overdue invoice letter - Final reminder (30 days)

After sending two overdue payment reminder letters, and still no acknowledgement or communication from the customer, the last stage is a final reminder. Sent at 30 days past due date, this final stage should show evidence of prior communications, a definite cut-off date for payment and outline any legal action you may take.

Final notice:

Subject line: URGENT: [Your company name] – Overdue Payment Final Notice – [Invoice number]

Dear [Name],

Following the lack of response to my previous communications, we now require your immediate attention to resolve this issue. The attached invoice is now overdue by [number of days overdue].

[Invoice number, balance, due date]

If we do not receive payment or acknowledgment of this issue before [cut-off date], we will pursue legal action to recover the costs of the invoice plus the late payment penalties as outlined in our payment terms.

Please confirm receipt of this email and advise as to when the invoice will be paid in full.

Kind regards,


Final thoughts and recap 

  • Late or unpaid invoices can have a significant negative impact on a business's cash flow. 
  • Unpaid or outstanding invoices can lead to increased debt and cost of capital, stifled growth opportunities, strained supplier relationships, and operational inefficiencies. 
  • Maintaining a healthy cash flow is crucial for the success and sustainability of a business. 
  • Effective invoicing and payment collection processes, as well as considering invoice financing solutions, can help mitigate the negative impact of overdue invoices. 
  • An overdue invoice letter serves as a formal communication to remind a client or customer that their payment is past due. 
  • The purpose of the letter is to prompt the recipient to make the payment promptly and to maintain a positive business relationship. 
  • The late payment letter should be professional, yet friendly, and clearly communicate the urgency of the situation while providing the necessary information for payment. 
  • Mention the outstanding invoice details: Provide specific details about the overdue invoice, including the invoice number, date, and the amount owed. 
  • Keep a record of all communication related to the overdue payment for future reference. 

In the world of business, dealing with outstanding invoices can be a challenging and uncomfortable situation. However, it is crucial to address the issue promptly to ensure you receive the payment you deserve. 

Remember, taking the right approach and adopting a proactive stance are essential in resolving unpaid invoices. We are here to support you every step of the way and provide the necessary resources to help you achieve success. 

Want to know more?

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