What does your invoice verification process miss if it only compares the invoice total to the purchase order total? Perhaps you recognize this approach: if the purchase order number exists and the total matches, the invoice is approved, and the line items below are not reviewed further. Checking only the total allows discrepancies to slip through that cancel each other out in the total: the total is correct, but the line items aren’t. If you check the total, you know the sum is correct—not that the invoice itself is correct. Your approach wasn’t negligence.
This page about 3-way invoice matching shows you what you can check in your own settings tomorrow: header or line-item level, how many documents you’re matching an invoice against, and what your tolerances are set to. A structured e-invoice delivers the invoice data in a structured format, but does not automatically compare it to a purchase order or receipt. That matching process remains a separate step. You can read more about this in the section on what structured invoices do and don’t solve. First, let’s look at the other side: what can you determine about matching at the total level?
What actually works well in terms of overall matching
In the AP environments we encounter, many tools and ERP systems match the invoice total against the purchase order total rather than line by line. Matching by total is quicker to set up. It usually works in the ERPs we encounter without any customization. And for an invoice with no line-item discrepancies, matching by total yields the same result as matching at the line-item level. These are isolated observations, not an explanation of how organizations configure their matching processes.
What does that mean for you? Your setting was not negligence. The difference with line level only arises with an invoice where line items differ. Matching at the total is a design choice with a consequence: differences that cancel each other out go unnoticed. What happens now with an invoice where the line items do differ?
What Goes Unnoticed
Take, for example—and not as a customer case—an invoice and a purchase order totaling €10,000. Line 1 is overbilled by €500, line 2 is underbilled by €500, and line 3 is correct. The difference in the total is €0.
| Rule | Invoice | Order Form | Difference |
| Rule 1 | €4,500 | €400 | + €500 |
| Rule 2 | €3,000 | €3,500 | – €500 |
| Rule 3 | €2,500 | €2,500 | € 0 |
| Total | €10,000 | €10,000 | € 0 |
Checking the total allows for discrepancies that cancel each other out in the total: in this example, the total is correct, but the line items are not. If you check the invoice at the line-item level, you’ll see line 1 and line 2 listed next to their corresponding purchase order lines. The example does not indicate how often this happens.
In the AP environments we’re seeing, discrepancies at the line-item level—such as incorrect items, price agreements that weren’t followed on a single line item, and overbilling hidden behind a partial shipment—cancel each other out overall. In the case of an incorrect item, the invoice line item lists something different from what you ordered. In the case of a price agreement that wasn’t followed, the price on that specific line item differs from what was agreed upon. In the case of over-invoicing hidden behind a partial delivery, a line item is invoiced for more than was actually delivered. So, what do you use to verify an invoice line item: just the purchase order, or also the delivery receipt and inspection report?
Matching two, three, or four times: what to check and where
The number of documents you attach to an invoice depends on the nature of the purchase, not on a single, blanket setting. With a software license, there is no physical receipt of goods. Below, you can see for each level which purchases this applies to and what it covers.
2-way matching: invoice vs. purchase order
2-way matching compares the invoice with the purchase order. It is suitable for purchases without a physical receipt, such as services, subscriptions, licenses, and framework agreements. In such cases, there is no receipt to compare the invoice against.
Detects: differences in price and, depending on your system, also in quantity compared to the order.
3-way matching: including the receiver
3-way matching includes the receipt of goods. It applies to goods. For an SME that purchases goods, 3-way matching is the basic check on those purchases: you verify that you are paying for what was ordered and received. This is a practical consideration for an SME that purchases goods.
Includes: in addition, billing for items that were not (fully) received.
4-way matching: when the evaluation counts
4-way matching adds the inspection step. It is used in situations where inspection is critical, such as manufacturing, pharmaceuticals, food, and construction. These sectors are just a few examples. In such situations, a delivery that has arrived has not yet been approved.
Includes: in addition, payment for goods that were received but rejected.
However, you can only compare line by line once you know which invoice line corresponds to which purchase order line.
Rule Link: The supplier does not use your words
That’s the problem: matching at the line level won’t work if the supplier uses a different description than the buyer. That’s true for exact-text matching. The supplier’s description isn’t necessarily the same as the buyer’s. In that case, exact-text matching won’t work.
Here’s an example: the purchase order says “A4 copy paper, 80 g/m²,” and the invoice says “White A4 paper, 80 g, 500 sheets.” In this example, both refer to the same item: 80-gram A4 paper. If you want to match an invoice with a purchase order and a receipt, a letter-by-letter comparison won’t help you here. To match at the line level, link invoice lines to purchase order lines based on meaning rather than exact text. If something isn’t listed on the purchase order, note it—don’t force it into a line.
For those managing the application: linking and comparing are two separate steps: first, you link each invoice line to a purchase order line; then, you compare the quantity and price for each pair. In our experience, AI is needed for the semantic linking, but not for the rest of the matching process. We do not specify a match percentage here. You can read more about our approach under “Process Automation at JUVO.” When is a discrepancy between two linked lines significant enough to block the invoice?
Tolerances: Where the Hidden Profit Lies
That’s what the tolerance determines: it defines which discrepancy between linked rules constitutes an exception. If your purchases vary in amount or type, a single overall tolerance will be too broad for some categories and too strict for others. Four principles apply to your invoice verification tolerances.
1. Percentage and absolute limit. A tolerance should have both a percentage and an absolute limit. Here’s a calculation example without an absolute limit: a 2% tolerance on an order of €1,000,000 allows for a difference of €20,000.
2. Asymmetric. Set your tolerance asymmetrically: be lenient when the supplier invoices less than what was ordered, and strict in the other direction.
3. Segmented. Segment your spending limits by category and price range, rather than using a single, blanket limit for a wide variety of purchases.
4. Clear minor discrepancies. Automatically clear minor discrepancies. What happens after an exception occurs is beyond the scope of this page; to learn more, read about what an exception actually costs you.
Two of the four principles—Principle 1 and Principle 4—involve configuring your existing system, to the extent that it allows, and eliminate some of the exceptions without requiring a purchase. The question remains: in which situations are the regulatory requirements and this configuration not worth the effort?
When matching at the line level isn’t worth the effort
Matching at the rule level isn’t always worth the effort. There are three situations in which it isn’t.
- Without lines on your order forms, there is no line level. Header matching—matching by total—only makes sense when there are no lines on the order form.
- When services are provided almost exclusively under a framework agreement, the risk lies in the price agreement and not in the rules.
- Without recorded goods receipts, 3-way matching is a false sense of security, and you have to start with purchasing. How will you determine tomorrow which of these situations you find yourself in?
First Steps Without Us
You can check your current matching status today without our help and without making a purchase. Start by following these steps.
- Check your tolerance. Check your ERP system to see what the tolerance is today, and whether there is an absolute limit in addition to the percentage.
- Take a sample. Manually review ten rejected and ten approved invoices from last month at the line-item level. Based on our own estimate, this will take about an hour, depending on the number of line items per invoice. This will give you an initial, useful answer.
What you’ll find there is an initial answer: your business case or your peace of mind—not a definitive verdict. What remains are the questions of what your ERP can already do, whether you’ll encounter more exceptions, and whether you need AI.
Frequently Asked Questions
These are the three objections that remain after the initial steps have been taken.
Can my ERP system already perform line-item matching?
In the ERP systems we encounter, you can often achieve line-level control in part through the tolerance settings. You can see what your current settings are in the first step above.
Will I get more exceptions if I match at the line level?
Matching at the line-item level may increase the number of exceptions in the short term. That is why tolerances and write-off rules are necessary, such as the four principles listed above.
Do I need AI to match at the line level?
In our experience, AI is needed for the semantic match, but not for the rest of the matching process. Comparing quantity and price per pair doesn’t require AI. To learn how this fits into the overall invoice workflow, read about how we automate accounts payable.
Want to know what your invoice matching lets through?
Start with your invoice process and see what automation delivers there.