FAQ – Construction invoices

You can find answers to your questions about construction invoices here. When it comes to invoicing, construction invoices are a special case in terms of their content, attachments and the processing workflow. For example, outside parties such as general planners or architects need to be consulted when checking invoices.

General information

Can a construction invoice be created in the Xrechnung standard?

Yes, even complex construction invoices can be created in the XRechnung standard. The XRechnung extension is particularly suited to the special requirements of construction invoices. This extension includes data fields and functions that are not available in the XRechnung standard. 

The XRechnung extension enables invoices to be issued with a hierarchical structure, where invoice lines can include any number of sub invoice lines. In addition, the extension enables XML attachments to be included, which is not possible in the XRechnung standard. This means that GAEB files, which are often used in the construction sector, can also be transmitted as supporting documents. More detailed information regarding the submission of supporting documents can be found in the other FAQs. 

Before an extension is issued, you should check whether the invoice recipient has the technical means to process it. In the ZRE and OZG-RE web submission forms, an extension is automatically generated when the “Add sub invoice line” function is used or when an XML file is attached.  

When issuing an electronic construction invoice, please make sure to indicate the correct invoice type code (BT-3). The following invoice type codes are available for construction invoices: 

  • 875: Partial construction invoice 
  • 876: Partial final construction invoice 
  • 877: Final construction invoice 

Using the correct invoice type code enables recipients to process your invoice properly.

When issuing an electronic invoice, do I also need to submit it in paper or PDF form?

No, please refrain from issuing or sending invoices in different formats, as this only adds to the processing burden for invoice recipients. This can result in delayed payment. Only the electronic invoice created in the XML file format can be accepted as the original.

What should I do if my own system is not yet able to create electronic construction invoices or if errors occur when I create them?

In this case, we recommend creating an electronic invoice via the web form of the relevant submission portal, entering the invoice data and attaching the original invoice as a scan or PDF file. As long as the invoice lines are clear in the attachment, you do not need to specify them again in the electronic invoice created in the web form of the submission portal. Whichever way you choose to issue your invoice, any information marked as required in the web submission form needs to be included (required information is specified in section 5 of the E-Invoicing Ordinance).

How can I submit supporting documents?

Attachments of up to 15 MB should be embedded directly in the invoice data file. You can find information on embedding attachments in the FAQs on the ZRE and OZG-RE submission portals. The XRechnung extension also makes it possible to embed XML attachments and thus add GAEB files to your invoice as supporting documents. If you are creating an invoice using one of the submission portals, you can upload XML files under the “Supporting documents” tab (in the ZRE) or the “Attachments” tab (in the OZG-RE). If you are using your own system to create an invoice, please ask the software company whether the XRechnung extension is supported and XML attachments can be embedded. 

If you wish to send attachments larger than 15 MB, the procedure varies depending on whether the receiving institution is connected to the OZG-RE or the ZRE. 


OZG-RE (Online Access Act-compliant Invoice Submission Portal) 

If you are sending your invoice to an institution connected to the OZG-RE, you can upload attachments of up to 200 MB via the web submission form by switching to the “References/Large attachments” tab. In the case of externally created invoices, large attachments can be uploaded under “Large Attachments” (see dropdown menu at the top left of the screen) and a link can be generated. This link can then be added to the invoice as a reference. 


ZRE (Federal Central Invoice Submission Portal) 

If you are sending your invoice to an institution connected to the ZRE, you can upload attachments of up to 98 MB via the web submission form by clicking on “Manage large attachments” (at the top right of any page or on the invoice dashboard). In the case of externally created invoices, large attachments can be uploaded under “Large Attachments” (see dropdown menu at the top left of the screen) and a link can be generated. This link can then be added to the invoice as a reference. 

As a rule, you need to ask the invoice recipient about any requirements for a link reference before sending an invoice via the OZG-RE or ZRE. If an invoice recipient cannot open a link, they can reject the invoice because it is not possible to review it. 

How should I submit exemption certificates?

The XRechnung standard does not currently provide a data field for indicating an exemption certificate. Because an exemption certificate is a confirmation letter issued by the tax office, it should be submitted as a supporting document along with your invoice.

When do the review periods for construction invoices begin?

The contracting authority’s review period begins when it receives your invoice and any supporting documents you have attached. The invoice issuer should contact the contracting authority with any questions on this matter.

What required fields need to be taken into account?

The buyer reference (Leitweg-ID) is required in the “Buyer reference” field (BT-10) in order to identify the invoice recipient. Additional invoice content is also often required in the construction sector in order to ensure smooth invoice processing between the contracting authority and contractor. The following information in particular is often required by public-sector contracting authorities when awarding contracts and should be included in an electronic invoice: 

  • Project reference (BT-11) 
  • Contract reference (BT-12) 
  • Purchase order reference (BT-13) 
  • Tender or lot reference (BT-17) 
  • Invoiced object identifier (BT-18) 
  • Buyer accounting reference (BT-19) 
  • Seller identifier (BT-29) 
  • Actual delivery date (BT-72) 
  • Invoicing period start date (BT-73) 
  • Invoicing period end date (BT-74) 

    Before sending your invoice, please check with the contracting authority what information they require in order to process the invoice.

    What should I do if the service recipient differs from the invoice recipient?

    If the service recipient differs from the invoice recipient, you should indicate the full name and address of the service recipient under “Delivery information” (BG-13). Make sure to use the correct buyer reference (Leitweg-ID) of the invoice recipient. 

    Please also note the VAT regulations regarding invoicing. According to these regulations, a c/o address is also sufficient for the aforementioned case (see section 14.5. (2) sentence 8 of the VAT Application Ordinance; UStAE). 

    Please also note any other requirements of the contracting authority or invoice recipient in this regard.

    Can collective invoices be submitted?

    No, it is not possible to issue collective or cumulative invoices for different contracts.

    How can I indicate allowances in an electronic invoice?

    The conditions of participation in federal and state construction tenders only provide for price reductions for the overall offer (“Document level allowances”, BG-20). Any allowances at invoice line level must be applied to the unit prices.

    How can I indicate charges and allowances in accordance with the material price escalation clause?

    For charges and allowances in connection with the material price escalation clause at invoice line level, please use “Invoice line charges” (BG-28) and “Invoice line allowances” (BG-27). The calculation used for these charges and allowances can be indicated in the fields “Invoice line charge reason” (BT-144) and “Invoice line allowance reason” (BT-139).

    How can I indicate retentions in an e-invoice?

    Retentions are agreed between the contracting authority and contractor when concluding a contract and are therefore treated separately from invoicing. It is not possible to indicate retentions explicitly in an electronic invoice. However, you can make reference to retentions in e-invoices by using the reference code “PMT” (payment information) in the “Invoice note” (BT-22) field.

    How can I indicate service status in partial construction invoices?

    In the case of partial construction invoices, the service status should be indicated as a percentage for some services that have not yet been fully rendered in order to invoice partially rendered services. A reduced service status is indicated as an imputed value at invoice line level in the “Invoiced quantity” (BT-129) field. This ensures that the actual invoiced amount is always processed as such. Please refrain from indicating the reduced service status as an allowance (in the BG-20 or BG-27 fields) in partial construction invoices. If necessary, further information regarding how the invoiced amount is calculated can be entered at invoice line level in the “Invoice line note” (BT-127) field.

    Do I need to submit corrective invoices if the amount payable has been reduced?

    No, it is not necessary to submit a corrective invoice corresponding to the paid amount.