We have a commitment with our suppliers. 

Woman working at an office typing on a computer

As part of working in partnership with our suppliers, we commit to paying everybody accurately and on time. To help us do this effectively, Omya prefers electronic invoices as the primary method of invoicing, unless stipulated otherwise by national legal requirements, which allows us to achieve environmental sustainability and more efficient invoice processing.

Advantages include immediacy of invoice receipt, no enveloping, posting or mailing costs, faster processing, greater accuracy and reduced environmental impact.

We use optical character recognition in our workflow to read and process most of our invoices. We ask all our suppliers and vendors to follow some straightforward steps that will ensure our systems can process your invoices properly and in a timely manner. 

Invoice requirements

Always quote our Omya purchase order number on the invoice.

Do not include a prefix, suffix or any other additional character that can affect automated recognition of the purchase order number. In most cases, a purchase order number will be sufficient, although there may be occasions when further information is required, such as a delivery number, bill of lading, or sales document.

Invoices submitted must meet the international invoicing standards:

  • Invoice must fulfill country-specific requirements established by legal regulations
  • The invoice must be addressed to the relevant Omya entity including its full name, address and tax identification number, where required
  • Full supplier, name, address, contact details and where required tax identification number must be provided
  • Document type “Invoice”* or “Credit Note”
  • Invoice date and number
  • Description and quantity of goods and/or services rendered 
  • Net unit price of goods and/or services
  • Breakdown of Tax amount payable by rate / exemption
  • Total Gross Value and currency
  • Indicate amount already paid in advance and final settlement required, where relevant

*Note: Proforma invoices and other documentation should not be sent to any of our iis email addresses but directly to the Omya requestor (who has requested them or appear in the order).

Please bear in mind that any invoices which do not comply with Omya or the forementioned invoice requirements will not be processed but returned to the supplier which may delay payment.

Payment Terms 

Omya settles its invoices according to the payment terms negotiated in advance by the Omya representative agreed in the contract and maintained in our ERP, unless specific terms are specified in our purchase order.

Invoicing alternatives

Omya like many other international companies, prefers electronic invoices as the primary method of invoicing. We encourage our suppliers to move from paper invoices to electronic invoices as it brings a number of advantages, including faster invoice processing, more secure delivery of invoices, reduced environmental impact, and reduced cost for enveloping, postage, and mailing.

Omya only accepts e-invoices unless national legal requirements prohibit it. 

    PDF invoices

Invoices must comply with the following criteria in order to be accepted by our systems:

  • The invoice must be created as a PDF file (no MS Word, Excel, jpg or tif files) and be sent as an attachment by email.
  • EachPDF file must contain a single invoice, however one email may include multiple PDF invoice files. 
  • Additional supporting documentation should be included, only when required by Omya, as additional pages of the PDF invoice.
  • The maximum email size is 35mb, with a maximum size per PDF of 20mb.
  • Do not print and scan invoices; instead please create your pdf file electronically to help us process it correctly.

Invoices should be sent to the following email addresses:

Download Email addresses list foR INVOICE SUBMISSION

It is also possible to submit your invoices via our vendor portal.

In case of query:

  • Please do not send any queries, payment reminders, requests, or statements to these iis email addresses, as they cannot be read.
  • All queries, payment reminders, requests or statements should be sent to the contact address listed in the section below “Status of your Invoice”. 
  • Proforma invoices and other documentation should not be sent to any of these addresses but should be sent directly to your Omya contacts (who have requested them or who appear in the order).

    E-invoicing (EDI and XML)

EDI connection is currently only offered for Italian domestic invoices. Notwithstanding, if you are a vendor with a volume higher than 100 invoices per year an EDI connection or submission in XML format might be possible. Requests should be submitted to the contact_ap email address of the corresponding country: 

DOWNLOAD Omya contact email addresses

    Paper invoices

Paper invoices are only accepted when there is no email address specified in Email addresses list for invoice submission or is required by national legislation. Paper invoices should be sent to Omya recipient entity to be entered into the relevant ERP by the accounts payable department. Therefore, the invoice must be clearly printed preferably on a A4 size paper or similar.

Vendor portal

If you submit your invoices electronically (either via EDI, XML or PDF), we recommend that you register for our vendor portal to be able to submit or view the status and expected payment dates for your invoices in real-time.

To apply for registration, please send an email requesting access to the relevant email address below with your invoice number for simple verification.


Once you have received your login details, your credentials will remain valid for all future invoices. This ensures seamless access to our system for ongoing invoice management and facilitates a continuous and efficient invoicing process.

The “Home” tab with the “My invoices” section of the dashboard allows you to submit your invoices, track in real time the status of your invoices and verify payment dates.

Status of your invoice       

Omya offers an enhanced and streamlined process for checking the receipt of invoices and their approval or payment status. The Vendor Portal eliminates the need for email communication and provides access in real time to the actual status of your invoices.

Furthermore, it is also possible to send payment queries via email directly to the contact email address of the invoiced entity, specifying the relevant information:

DOWNLOAD Omya contact email addresses


Always quote the Omya purchase order number on the invoice without any prefix or suffix that can affect the recognition of the order number. Include additional relevant references, such as delivery number, bill of lading, sales document, or any other references agreed with Omya.

In most cases, Omya accepts only PDF invoices, either through our iis-Mailboxes that you can find in EMAIL ADDRESSES LIST FOR INVOICE SUBMISSION or directly submitted via our Vendor Portal. However, if national legal requirements prohibit the use of PDF, alternative formats may be necessary.

The maximum size for email attachments is 35MB, and each PDF (one invoice per PDF) file should not exceed 20MB in size.

Any additional supporting documentation should be included within the PDF invoice itself but only when requested. There should be no separate additional attachments.

PDF invoices should be sent to the email addresses specified in the document. Please refer to the mentioned EMAIL ADDRESSES LIST FOR INVOICE SUBMISSION for the correct email addresses.

No, queries, payment reminders, requests, or statements should not be sent to the email address mentioned for invoice submission. Instead, they should be sent to the Omya contact email addresses.

We recommend you register for the vendor portal, where you can view the status and expected payment date of your invoices in real time. Send an email requesting access to the email address mentioned in the Omya contact email addresses document, including your own invoice number for verification.

No, proforma invoices and other documentation should be sent directly to your Omya contacts who have requested them or who appear in the order. The email addresses listed are specifically for sending PDF invoices.

Send an email to the email address provided in the Omya contact email addresses document, requesting access to the vendor portal. Include your name and current invoice number for verification. Once your access is granted, you will receive a welcome email with login credentials and a link to access the Vendor Portal. 

For any question or issues regarding our invoicing process, please consult the status of your invoice on the Vendor Portal or send an E-Mail to our Omya contact email addresses.