Invoice validation is the process of checking that a vendor invoice is genuine, accurate, and matches what your business actually ordered and received. The invoice validation process includes verifying vendor details, matching the invoice against purchase orders and delivery records, checking calculations, and confirming compliance before approving payment.
About 25% of invoice errors slip through AP processes undetected, leading to overpayments, duplicate payments, and fraud. This guide explains what invoice validation covers, the steps involved, and how to improve accuracy.
Invoice validation is the set of checks your accounts payable team performs to confirm that an invoice is legitimate and correct before approving it for payment. It answers three questions: is this invoice real, does it match what we ordered, and are the amounts correct?
Without invoice validation, your business is exposed to overpayments, duplicate invoices, and fraudulent billing. A single unvalidated invoice can result in paying for goods you never received, paying the wrong amount, or paying the same invoice twice.
The invoice validation process applies to every invoice your team handles, whether it is tied to a purchase order or not. PO-backed invoices are validated through matching, while non-PO invoices require manual review and separate approval to confirm the expense is legitimate.
Invoice validation protects your business from financial loss. The checks in the validation process catch errors and fraud before money leaves your account, not after.
Without validation, your team might pay the same invoice twice if a vendor resubmits it or if it arrives through multiple channels. The invoice validation process includes a duplicate check that flags invoices with the same vendor, amount, and invoice number. This single check can save thousands of dollars per year.
Fraudulent invoices are designed to look legitimate. Invoice validation catches them by verifying the vendor against your approved supplier list, confirming a matching purchase order exists, and checking that the billing details match your records. Without these checks, a fake invoice can slip through and get paid.
Every invoice that gets paid is recorded in your accounting system. If the invoice data is wrong, your financial records are wrong. Invoice validation confirms that amounts, tax calculations, and GL codes are correct before the data enters your books.
Disputing a payment after it has been made is harder than catching the error before payment. A reliable invoice validation process means fewer payment disputes, fewer correction requests, and smoother communication with your vendors.
The invoice validation process follows a consistent sequence of checks. Each step verifies a different aspect of the invoice before it moves to approval.
The first step is confirming that the invoice has not already been received or paid. Your team or system checks the invoice number, vendor name, amount, and date against existing records. Roughly one in five invoices gets flagged as an exception during processing, and duplicates are one of the most common causes.
Confirm that the vendor on the invoice is in your approved supplier list and that the billing address, contact information, and bank details match what you have on file. Any changes to vendor payment details should be verified directly with the vendor, as this is a common target for fraud.
For PO-backed invoices, check that the invoice references a valid purchase order number. The PO confirms that the purchase was authorized and establishes the agreed-upon items, quantities, and prices. If there is no PO, the invoice follows a separate non-PO approval workflow.
Two-way matching compares the invoice to the purchase order. Three-way matching adds the goods receipt or delivery note as a third document. The goal is to confirm that what was ordered matches what was delivered and what is being billed. Discrepancies in quantity, price, or items get flagged for review.
Check that the line item totals, subtotals, tax amounts, and discounts on the invoice are calculated correctly. Calculation errors are easy to miss when reviewing invoices manually, especially on invoices with many line items. Even small per-unit errors add up across large orders.
Confirm that the invoice meets your company's internal policies and any applicable tax or regulatory requirements. This includes verifying that the correct tax rate was applied, that required fields are present, and that the invoice format meets local legal standards.
When any validation check fails, the invoice becomes an exception that requires manual investigation. Common exceptions include price differences between the invoice and PO, quantity mismatches, missing PO numbers, and unrecognized vendors. Top-performing AP teams resolve exceptions in about 3 days, while the average team takes twice as long.
Once all validation checks pass and any exceptions are resolved, the invoice is approved and scheduled for payment. The approver confirms that the invoice is legitimate, accurate, and ready to pay. The validated invoice and all supporting documents are archived for future reference and audits.
Knowing the most frequent errors helps your team focus validation efforts where they matter most.
The price on the invoice does not match the price on the purchase order. This happens when vendors apply price increases without notice, use the wrong rate, or make calculation errors on tax or discounts.
The invoice bills for a different quantity than what was delivered. This is common with partial shipments where the vendor invoices for the full order, or when goods are damaged in transit and the receiving team logs a lower count.
The invoice does not reference a purchase order, or it references the wrong one. Without a valid PO, the invoice validation process cannot match the invoice to an authorized purchase, and the invoice stalls until the issue is resolved.
The same invoice arrives through multiple channels or gets resubmitted by the vendor. Without a duplicate check, both copies can move through the validation process and result in a double payment.
The vendor's bank account or address on the invoice differs from what is on file. While legitimate changes do happen, altered payment details are also the most common method used in invoice fraud schemes. Every change should be verified directly with the vendor through a known contact.
Small changes to your invoice validation process can significantly reduce errors and speed up processing time.
Nearly half of all invoices are still received in formats that require manual data entry. Automating data capture with AI-powered tools eliminates typing errors and gets invoice data into your system faster. This gives your team clean data to validate against instead of data that might already contain entry mistakes.
Automated two-way and three-way matching compares invoices against POs and receipts instantly. Invoices that match perfectly can be approved without human involvement, freeing your team to focus on the exceptions that actually need attention.
Define clear steps for handling each type of exception: who investigates, who contacts the vendor, and what the escalation path is. A standardized workflow prevents exceptions from sitting in someone's inbox for days.
Review your approved vendor list and payment details on a regular schedule, not just when something looks wrong. Proactive vendor validation catches outdated or compromised payment details before a fraudulent invoice takes advantage of them.
The table below compares manual and automated invoice validation across the areas where the difference is most significant.
| Validation area | Manual process | Automated process |
|---|---|---|
| Duplicate detection | Relies on memory and spreadsheets | Automatic flagging in real time |
| PO matching | Manual line-by-line comparison | Instant cross-reference |
| Calculation checks | Spot-checked or skipped | Every field verified automatically |
| Exception resolution | 6+ days on average | ~3 days (top performers) |
| Error detection rate | ~75% (25% slip through) | 95%+ with automated rules |
| Audit trail | Paper files and email threads | Complete digital record |
Lido automates the data capture step that feeds your invoice validation process. It reads invoices from any vendor in any format and extracts vendor name, invoice number, line items, quantities, totals, and PO numbers into structured columns. Clean, accurate data from the start means your validation checks run against reliable information instead of data that was typed in by hand.
The platform connects to your email, shared drive, or cloud storage and processes invoices as they arrive. It works without templates, so new vendors are handled immediately with no setup. Extracted data exports to Google Sheets, Excel, QuickBooks, or CSV. A 24-hour refinement window lets you flag any extraction error, and Lido corrects it at no extra cost.
Now that you understand what the invoice validation process involves, you can identify which checks in your current workflow need the most improvement and where automation can help.
Invoice validation is the process of checking that a vendor invoice is genuine, accurate, and matches what your business ordered and received. It includes verifying vendor details, matching the invoice to purchase orders and delivery records, checking calculations, and confirming compliance before approving payment.
The invoice validation process includes checking for duplicates, verifying vendor details, confirming the purchase order, performing two-way or three-way matching, verifying calculations, checking compliance, resolving exceptions, and approving for payment.
Invoice validation prevents overpayments, duplicate payments, and fraud. About 25% of invoice errors go undetected without proper validation, which leads to financial losses, inaccurate records, and strained vendor relationships.
Three-way matching compares three documents: the vendor invoice, the original purchase order, and the goods receipt or delivery note. It confirms that what was ordered matches what was delivered and what is being billed before the invoice is approved for payment.
Start by automating data capture with AI-powered tools that extract invoice data without templates. Then add automated matching to compare invoices against POs and receipts instantly. Invoices that pass all checks can be approved automatically, while exceptions are routed to your team for review.
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