What are Duplicate Invoices
Duplicate invoices are a hidden threat in trade business accounting. Whether caused by manual entry, vendor habits, or outdated processes, these errors lead to unnecessary payments that quietly chip away at your bottom line. While one or two duplicates may seem minor, they can quickly add up—especially when your team processes hundreds of invoices every month.
A typical small-to-mid-sized business receives six duplicate invoices per month on average, each worth over $2,000. That’s potentially $12,000 lost monthly—and that’s not including the hours your accounts payable (AP) team spends tracking down and fixing the issue.
Common Causes of Duplicate Invoices
As any business owner knows, no system is perfect. It’s why it’s vital to cover vulnerabilities to prevent mistakes and problems from happening. This includes preventing duplicate invoices by determining their root causes.
1. Manual Data Entry Errors
Duplicate invoices are caused by the vendors’ AP teams mistakenly re-entering the same invoice due to typing errors or a lack of invoice number recognition. As of 2025, 86% of small and medium-sized businesses manually enter data, increasing error risks.
2. Multiple Invoice Submissions from Suppliers
Vendors may submit multiple invoices for several reasons:
- It is their standard to send the same invoice on paper and in digital format.
- They may re-send the same invoice due to delayed payments as a reminder or a follow-up.
Submitting multiple invoices triggers multiple payments. Because these duplicates only have slight differences, they may fool accounting systems into accepting them as new invoices.
3. Lack of Standard Operating Procedures (SOPs)
When a trade business has no standard operating procedure (SOP) for invoice processing, its employees may struggle to verify if an invoice has already been paid.
4. System and ERP Glitches
The trade business’s accounting system or enterprise resource planning (ERP) software may be experiencing bugs or integration issues, causing multiple payments for the same invoice.
5. Inefficient Invoice Management Systems
A trade business with poor filing, tracking, and storage systems can cause invoices to not be properly marked or archived, making it difficult to detect which ones have already been settled.
6. Fraudulent Activity
External and internal fraud can use the invoice processing system for their own profit. A supplier may intentionally trick the system with the same invoice with slight changes. An employee may also intentionally process duplicates and request refunds to pocket the money.
7. Relying Solely on Manual Review
While accounts payable teams are skilled in invoice processing, the lack of automation detection tools can leave a trade business vulnerable to human errors.
ERPs Cannot Detect Duplicates: Why You Need Automation Detection Tools
ERP (Enterprise Resource Planning) software is used to handle invoice capture, validation, approval, and payment. However, they do not have the features to reliably detect invoice duplicates due to the following:
- Most ERPs don’t have the AI to scan invoice line item descriptions or recognize contextual similarities. For example, an ERP may treat “DeWalt 20V Max Drill Kit” as different from “Cordless Power Drill.”
- ERPs rely heavily on exact invoice number matches and may not detect slightly altered numbers, such as 821345 and 821254.
- Vendors may submit multiple formats (e.g., a paper invoice and a digital one) that look slightly different, causing the system to process them both as new.
Detect Duplicate Invoice Errors from Accounts Payable with InvoiceIQ Automation
Most of the issues discussed above are symptoms of manual invoice checking inefficiencies. Without automation, duplicate invoice errors are much harder to prevent and detect.
AP automation software like InvoiceIQ uses AI and pattern recognition to:
- Detect duplicate invoice submissions
- Compare invoice pricing to special pricing agreements negotiated with vendors
- Reduce fraud, processing mistakes, and approval delays
By streamlining the accounts payable process, businesses can eliminate the hidden costs of manual work and regain control of their financial operations.
