E-Invoice FAQ
Answers to frequently asked questions from practice
- 20 practical questions answered professionally
- Mandatory fields & references according to EN 16931
- Concrete recommendations for SAP
Why doesn’t my e-bill contain any weight information?
The European e-invoicing standard EN 16931, on which XRechnung and ZUGFeRD are based, does not provide for separate data fields for weights . Weight information is not required for a VAT-compliant invoice and was therefore not included in the data model. If your customers need weight information, there are three ways: If you invoice by weight, the weight is displayed as the invoice quantity with the unit “kg” in the document. Informational weights can be transferred as an article attribute (BG-32) or as free text at item level. In the hybrid ZUGFeRD format, the PDF part also continues to contain the complete invoice image, including all weight information.
Why is the customer’s order date missing from the e-invoice?
The EN 16931 standard only provides for the buyer’s order number (BT-13), not the order date. The clear assignment to the invoice recipient is done via the order number – the date is not required for this and is not provided for in the XRechnung data model. In the ZUGFeRD format (EXTENDED profile), the order date can be transferred in a structured manner; in the XRechnung it is alternatively possible to specify it as free text.
What happens with collective invoices with multiple delivery note numbers?
The EN 16931 standard allows only a single delivery note reference (BT-16) at document level. In the case of collective invoices with several deliveries, the ZUGFeRD EXTENDED profile therefore transfers the delivery note numbers item by item: Each invoice item bears the number, item, and date of “its” delivery note. In the XRechnung and in the ZUGFeRD profile EN 16931 (COMFORT), delivery note references are not permitted at item level – this is where the leading delivery note is transferred at document level. If you need to obtain the complete delivery note for collective invoices, you agree on the EXTENDED profile with the invoice recipient.
What happens with collective invoices with multiple order numbers?
At document level, the standard only provides for a purchase order reference (BT-13) and an order reference (BT-14). If a collective invoice is based on several orders, the reference of the leading order is transferred. The ZUGFeRD EXTENDED profile provides item-specific assignment: Each invoice item contains the order number and the order date of its order. In the XRechnung and in the COMFORT profile, only the order item number (BT-132) is provided at item level. Note: Some (especially public) invoice recipients require exactly one purchase order number per invoice – in this case, an invoice split per order is recommended, which you can set in SAP SD via the copy control.
Does the return credit note need to be related to the invoice or the order?
No. The EN 16931 standard provides for the reference to the previous invoice (BT-25) as an optional field; it is also not required for VAT purposes for a return credit. Nevertheless, we recommend that you enter the original invoice number if it can be determined in the system – it is transferred in the “Previous invoice” field (BT-25), which may even occur several times. An order reference can also be transmitted via the order reference (BT-14/BT-13). If no structured reference is available, the number can be given as free text (BT-22). The invoice recipient benefits from this with automatic document matching.
I’m sending invoice IDocs (EDI) today – what do I have to do?
A classic INVOIC IDoc is not an e-invoice in the sense of §14 UStG, because it does not comply with the EN 16931 standard. You may continue to operate existing EDI connections on a transitional basis with the consent of your customers – for EDI procedures, the transitional period applies until the end of 2027. From 2028, EDI formats will only be permitted if all the information required by EN 16931 can be extracted correctly and completely from them. Our recommendation: Keep established EDI routes for the time being and introduce the dispatch of XRechnung or ZUGFeRD at the same time. MailCenter Invoice Pro generates both formats directly from your SAP billing document – without interfering with your existing IDoc processes, controllable per customer.
What to do with the "no-Russia clause" (Art. 12g Regulation (EU) 833/2014)?
The No Russia clause is a contractual obligation towards your customer in the third country and not a mandatory indication of the invoice – the EN 16931 standard does not provide a separate data field for it. If you still want to include the note on the invoice (common practice in export), transfer it as a free-text remark at document level (BT-22). With ZUGFeRD, the note also appears in the PDF invoice image. Please note: The reference on the invoice does not replace the contractual agreement required by Art. 12g – it merely documents it. The clause is not relevant for purely domestic transactions that are subject to the German e-invoicing obligation.
Why doesn’t a fax number appear in the e-bill?
Because the standard simply does not provide a field for this: In the data model of EN 16931, on which XRechnung and ZUGFeRD are based, the contact block contains only name, telephone number and e-mail address. One fax element was deliberately not included in the standardization process – e-invoicing relies on electronic accessibility via e-mail. The absence of the fax number is therefore not a gap in your invoice, but a deliberate simplification of the standard. With the hybrid format ZUGFeRD, the fax number remains visible in the PDF invoice image if your form outputs it.
Why is our company name truncated in e-billing?
EN 16931 only has one one-line name field (BT-27/BT-44) for each party – no second line as in the letterhead. Multi-line company names must therefore be merged in the master data, otherwise additions such as “c/o” will be lost or end up in the middle of the field. The lever lies in the quality of the master data, not in the invoice format.
Why does the e-bill show "bank transfer" even though there is a SEPA direct debit mandate?
A mandate alone is not enough: Only when the payment method is set on the receipt itself does the system transmit Code 59 including mandate reference and creditor ID. If this assignment is missing, “Transfer” automatically takes effect – regardless of the stored mandate.
What happens if a credit becomes negative overall?
The final amount of an e-invoice must be positive. If a credit memo becomes mathematically negative due to return goods or bonuses, it semantically tilts to the invoice (type 380) and vice versa – this must already be taken into account when creating the document.
Are negative items (deposit return, discount in kind) allowed in the e-invoice?
No, the sum rules of EN 16931 do not allow negative row totals at will. It is common to convert them into billing charges at document level or zero lines for free items.
Why do cent differences arise in VAT?
BR-CO-17 requires: Tax amount = tax base × rate per tax category, calculated at the total level. If you round line by line instead, you will deviate by cents and fail at the validator – a common mistake with collective invoices.
What must be included in the e-invoice for tax-exempt transactions?
The tax category and reason for exemption (text or VATEX code, BT-120/121) are required. Exception: In the case of category Z (zero rate), no reason for exemption may be given.
What is the minimum master data required for a valid e-invoice?
The VAT ID No. of the seller, in the case of a bank transfer, an IBAN and correct addresses. Missing VAT ID or IBAN are the most common validation errors (BR-CO-26/27).
What is the routing route ID and when do I need it?
The Leitweg ID (BT-10) is only mandatory for invoices to authorities (B2G). It is not needed in B2B business.
Does the e-invoicing obligation also apply in the credit note procedure (self-billing)?
Yes. The buyer issues, but the supplier remains the “seller” in the receipt – whose VAT ID no. and IBAN must be correct.
What to do with invoices with tens of thousands of items?
It is recommended to condense by article, tax rate and price, the detailed list follows as an embedded attachment (BG-24). The sums must be exactly retained.
Does the obligation also apply to rental and standing invoices?
Yes, continuing obligations such as rental or maintenance contracts are just as obligatory as individual invoices.
What is in store for us in France?
From 1 September 2026, all companies subject to FR VAT must be able to receive e-invoices, with dispatch to follow in stages in 2026/2027. The exchange takes place exclusively via approved platforms (PA).
Comparison table: Reference fields in comparison – ZUGFeRD EXTENDED, COMFORT and XRechnung
| Field | ZUGFeRD EXTENDED | ZUGFeRD COMFORT (EN 16931) | XBill |
|---|---|---|---|
| Delivery note number (header) | ✅ one (leading delivery, BT-16) | ✅ one (BT-16) | ✅ one (BT-16) |
| Delivery note number (item) | ✅ Number, position, date per line | ❌ not permitted by default | ❌ not permitted by default |
| Sales Order Number (Head) | ✅ one (leading order, BT-14) | ✅ one (BT-14) | ✅ one (BT-14) |
| Sales Order Number (Line) | ❌ | ❌ | ❌ |
| Order number (head) | ✅ one (leading order, BT-13) | ✅ one (BT-13) | ✅ one (BT-13) |
| Order number (item) | ✅ per item from the respective order | ❌ Order item no. only. (BT-132), if maintained | ❌ Order item no. only. (BT-132), if maintained |
| Order Date (Head) | ❌ | ❌ no field in the standard | ❌ no field in the standard |
| Order Date (Line) | ✅ per item | ❌ | ❌ |
Reading aid:
- “A (leading …)”: EN 16931 provides only one reference field at the document level. In the case of collective invoices, the leading document is transferred; only EXTENDED offers position-specific assignment.
- ❌ with COMFORT/XRechnung is not a product restriction, but a specification of the standard – the elements are not allowed there and would be rejected by the recipient validator.
- Recommendation: For item-specific delivery/order reference (e.g. automatic goods receipt comparison), agree on ZUGFeRD EXTENDED with the recipient; in the case of XRechnung to public clients, if necessary, invoice split per order.
Explore our solutions
Your SAP Partner
munich enterprise software GmbH
Industriestraße 31
82194 Gröbenzell
Opening hours:
Mon. – Fri.: 09:00 am to 16:00 pm
+49 89 2154 689 80
