Avoid­ing mis­un­der­stand­ings when talk­ing about SAP® ven­dor in­voices

The term “Vendor invoice” in SAP® has more than one meaning, which sometimes may cause confusion when analyzing data. In this article I will explain this in detail based on the example of an invoice from a vendor which is based on a purchase order. We will look at the same invoice, but they differ in the SAP® materials management module (SAP® MM) and the SAP® Financials module (SAP® FI). The SAP® tables which are concerned as well as the SAP® transaction codes will also be listed in that context.

Let’s look at a real-life example, which I have witnessed several times already when supporting analytic field work based on SAP® data or data analytic projects for Internal Audit departments:

An auditor identifies a vendor invoice, which is a potential finding, and he needs to get more details regarding that document. He has a screenshot of a purchase order, and it contains an invoice document number under tab “Purchase order history”.

He contacts a colleague from the accounting department, asking for details. The conversation goes as follows:

Auditor: “Good morning. Could you do me a favor please and look up a vendor invoice, which I think may have been paid twice? Invoice number which is concerned is 5105607484, and it is from 2003 already.”

Accounting Clerk: “Sorry, I tried to look up the number, but the system tells me that it cannot be found. Are you sure that the number is correct?”

Auditor: “I just double-checked in my Excel™ spreadsheet– the number is correct, and as we do not archive our SAP® data it has to be in our system!”

Who is right, who is wrong? What could be the problem here? To clarify, let’s look at SAP®‘s standard behavior when it comes to invoices which were entered in reference to a purchase order:

Usually within the P2P-process (Purchase-to-Pay), after issuing a purchase order and getting the goods, we receive an invoice from the vendor as well. That invoice document can be entered in SAP® with reference to the appropriate purchase order by using SAP® T-Code “MIRO”. Once the data is complete and the document gets saved (posted), SAP® creates a document number, for example the number 5105607484 which is used in our example.

But why couldn’t it be displayed? You might know SAP® transaction FB03 (Display financial document), but it only gives us an error message:

Transaction FB03 fails - is the document number incorrect?

As the screenshot shows, the vendor invoice number was not found – however we know it exists as it is listed in the purchase order history. The reason is that SAP® usually creates not one but (at least) two invoice documents whenever an invoice is entered with reference to a purchase order: One is the materials management (MM) version of the invoice; the other document is the financial (F) version of the invoice. Both are based on the very same business transaction and created parallel automatically by only one data entry process, so the user usually does not notice this. However, technically speaking

  • each one gets a different/own SAP® document number assigned
  • both versions are stored in totally different SAP® tables and
  • if you want to display it successfully, you will need different SAP® T-Codes for each

The “Materials Management (MM) version” can be displayed by using SAP® transaction MIR4. (It requires document number and fiscal year, which are the key fields of the tables in which the MM invoices are stored. The tables in this case are RBKP and RSEG, containing header- and line item information).

The good news is that the MM invoice and the FI invoice are linked. By clicking on “Follow-up documents” a list of related documents will be displayed. The screenshot makes transparent that the FI invoice document number is 5100005176; it differs from the MM invoice document number.

Double-clicking displays the FI version of the vendor invoice. This allows you to leave the SAP® MM module and move to the SAP® FI module. All amounts etc. are of course the very same, as it is based on the same entries and the same business transaction. The FI invoice document can be displayed direct for example with SAP® T-Code FB03. Before it did not work because we used the wrong invoice document number, the MM one, not the FI one. If we use the correct one this time (which is 5100001576, not 5105607484) it works fine. (Additionally the FI transaction FB03 requires fiscal year plus the company code which is concerned. The FI invoice is stored in SAP®‘s general ledger tables BKPF and BSEG).

The document header contains interesting information, which can be displayed by clicking on the „hat“-icon. It shows the SAP® T-Code which was used to enter the document. In our case, this was transaction MIRO, which in fact created both documents, the MM as well as the FI version of our vendor invoice. Also you might notice the „Ref. Key“ field, which contains several numbers which look similar to our MM invoice number: 51056074842003. In fact it is a combination of the MM invoice number 5105607484 and the fiscal year 2003.

Summing up, one business transaction like a vendor invoice with reference to a purchase order results automatically in two different SAP® documents, which may have completely different document numbers, data stored in different tables for each version of that invoice and different SAP® transactions for displaying them. Both invoice versions are “linked”, you can branch off from the MM invoice to the FI version, or look at the FI version and identify the corresponding MM invoice number by looking at the “Reference Key”.

To complete our example, let’s look at a purchase order again. Sometimes you may start your detail analytic work with displaying a purchase order as one of the first elements of the P2P-cycle. To do so, you use SAP® ME23n, and this one belongs to the SAP® materials management module MM. Accordingly, if you look at invoice receipts which are listed under tab “Purchase order history”, the numbers that are listed there are SAP®MM invoice numbers, not FI invoices:

On the contrary, if you perform a list display of vendor documents by using transaction FBL1n, then you are within the SAP® financials module, which means all invoice numbers listed there are FI invoices.

If a reference to a purchase order exists, you can find out about the number of the MM invoice as shown above by looking at the header details, namely the field „Ref. Key2. (Side note: For invoices without reference to a purchase order, the reference key is equal to the FI invoice number. However, to identify invoices without purchase orders, there are other – and better – ways.)

The next time you have to look up or ask for vendor invoice details, it might be helpful to make sure which document is concerned: Is the document number belonging to a materials management invoice, or is it an invoice based on the financial module? Depending on the department you are talking to (procurement vs. accounting) this might make a difference, and sometimes confusion and misunderstandings can be avoided by already differentiating properly upfront.

The following table gives a summary based on our concrete example:



Module / DocumentCreated by Displayed withStored inDocument number example
Materials Mgmt / MM-InvoicePosted with SAP® T-Code MIROMIR4

RBKP (Header)
RSEG (Line item)

5105607484 (Nr.)
2003 (Fiscal Year)
Financials / FI-Invoice

Created automatically by SAP®

FB03 BKPF (Header)
BSEG (Line item
5100001576 (Nr.)
2003 (Fiscal Year)
1000 (Company Code)


I hope this article was interesting and helpful for your daily analytic work.

For any comments on this article, feel free to write us at info@dab-gmbh.de.

To contact the author you can also use LinkedIn or XING (you may have to login first before you can access these links).

LinkedIn: http://de.linkedin.com/pub/stefan-wenig/54/1b8/b30

XING: https://www.xing.com/profile/Stefan_Wenig2?sc_o=mxb_p

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