MDPI Invoice, Discount, Payment, and Refund FAQs

Below are some payment troubleshooting suggestions:

• Ensure your credit card is authorised for international transactions.
• If you are unable to access payment.mdpi.com, please try using a different web browser (if available), or try disabling any add-ons in your browser that might be blocking the transaction.
• Check if your credit card has a spending limit.
• If the page returns an error after entering your credit card details, your card provider may have blocked the transaction. To resolve this issue, you will need to contact your credit card provider.
• International credit cards often require a two-factor authentication process, such as 3D Secure, for international transactions. This may involve verifying your identity with the card issuer by providing a code sent via SMS or email. You may be required to complete both steps in the process before payment can be authorised.

If you are unable to resolve the issue, please see our Payment Instructions for alternative payment options.

The corresponding or submitting author can update the invoice details after the paper’s submission and before acceptance. To edit the invoice address, email, or currency, follow the link provided in the APC confirmation email or go to Submissions Menu - Invoices.

Yes, the APC can be split into up to eight separate invoices. To request this, please contact the Accounts Receivable Team and specify how many parts you need, the amount for each part, and the billing address for each invoice (you may use the table below as a guide). Each portion will be issued as its own invoice with a unique invoice ID and payment link. All invoices follow the same payment terms.

Info	Split Invoice 1	Split Invoice 2	Split Invoice 3
APC amount and currency
Billing an individual/institution?
Institution name (if applicable)
Department (optional)
First name/family name
Address (street, city, postcode)
Country:
Email:
VAT/tax number (if billed to institution)
Purchase order number (if required)
Any additional required codes/text

Yes, we support several platforms for e-invoicing (for example B2B Router, Chorus Pro, and Coupa). Please submit your request to the Accounts Receivable Team, including all required information and necessary codes, to ensure successful processing.

Some common e-invoice formats, platforms, and required information:

**FACe: **

English (Español) • Managing Body (Órgano Gestor) • Accounting Office (Oficina Contable) • Processing unit (Unidad tramitadora) • Proposing Body (Órgano Proponente)

**PEPPOL: ** • PEPPOL ID Chorus Pro: • SIRET number/SIRET • Service code/Code service • Commitment number/N° d'engagement

**XRechnung: ** • Leitweg-ID

**vendors@gov: ** • Ministry/Statutory Board • Department • Sub-Business Unit • For the attention of

Yes, we accept Purchase Orders (PO’s). Please send your PO’s to ✉️ and indicate the invoice/manuscript ID in the subject line.

All quoted APCs are exclusive of VAT. VAT or equivalent taxes will be added as follows:

• Switzerland: Local VAT applies.
• Japan: Japanese Consumption Tax (JCT) applies.
• Taiwan: A 5% VAT applies only to individual (B2C) customers. No VAT applies to invoices issued to Taiwan institutions or companies (B2B).

Authors in all other locations should account for VAT in their country under the reverse charge mechanism, whereby the recipient of a service from a foreign company pays the VAT directly to the local tax office. Please check with your institution for guidance on local VAT.

MDPI offers the following waivers and discounts:

Affiliation Discount: Authors affiliated with institutions participating in MDPI’s Institutional Open Access Program (IOAP) or who are members of a partnered Society may be eligible for a discount.

Reviewer vouchers: Reviewers who provide timely and substantial comments receive reviewer discount vouchers. These are issued after the final decision on the reviewed paper. Reviewers may apply one or more vouchers to reduce their APCs. Please note that vouchers are non-transferable and can only be used for papers where the reviewer is listed as an author.

All vouchers and discounts must be applied before a manuscript is accepted for publication. Vouchers cannot be applied once the APC invoice has been issued.

Reviewer vouchers: Discount vouchers are listed under the Submissions Menu in the Discount vouchers are listed under the Submissions Menu in the Discount Vouchers list. Authors may link multiple email addresses to their profile to use all vouchers issued to them by MDPI.

Please add your voucher code when submitting your paper. Doing so will automatically apply the discount to your APC. If your paper is rejected, the voucher can be reused for your next submission. If you need assistance applying your voucher, please contact your assigned editor.

Affiliated Discount: Authors affiliated with institutions participating in MDPI’s Institutional Open Access Program (IOAP) or a partnered Society receive a discount per paper published in an MDPI journal. The IOAP/Society discount may be combined with reviewer vouchers.

All vouchers and discounts must be applied before manuscripts are accepted for publication. Vouchers cannot be applied once the APC invoice has been issued.

The discount can be added to the invoice up until the paper’s acceptance for publication. Please contact your Assigned Editor. Once the final invoice is issued, the invoiced amount cannot be changed.

We accept payments via card, wire transfer, PayPal, and cheques. For more information, please refer to our Payment Instructions.

We accept payments in Swiss francs (CHF), US Dollars (USD), Euros (EUR), Pounds Sterling (GBP), Japanese Yen (JPY), and Canadian Dollars (CAD).

Many common payment errors can be easily resolved. Try the following steps: • Ensure that your credit card is authorised for international transactions. • If you cannot access Payment Instructions, try a different web browser or disable any add-ons that might block the transaction. • Check that your credit card is within its spending limit and has sufficient funds. • If an error occurs after entering your card details, your card provider may have blocked the transaction – please contact them directly. • International credit cards often require two-factor authentication (e.g., 3D Secure). You may need to verify your identity with a code sent by SMS or email before the payment can be authorised. If the issue persists, please contact the Accounts Receivable Team for assistance.

Depending on your payment method, it may take some time for the payment to reach our accounts and be registered:

Card payment: 1 – 2 days PayPal: 1-2 days International wire transfer: 1 – 14 business days Cheque payment: over one month (if sent via international mail)

A common reason for delay is a missing payment reference. Always include the manuscript ID (e.g., journalname-1264567) or invoice number in your payment reference.

If you have paid and wish to pause reminder emails while we confirm your payment, please send proof of payment to the Accounts Receivable Team.

If an invoice is underpaid, another invoice will be issued for the remaining balance. Common causes include unaccounted-for bank or PayPal fees, or currency conversion differences.

If an invoice is overpaid or paid twice, please contact the Accounts Receivable Team to request a refund. Please note that you will be responsible for any related bank or transaction fees.

Unfortunately, installment payments are not available for APCs. However, if you need to split the payment due to card limits, please let us know the amount you would like on each invoice, and we can issue multiple invoices accordingly.

No, MDPI only issues an APC invoice once a manuscript has been accepted for publication.

Yes. You can make a deposit for future publications or request a proforma invoice to make a prepayment before the APC invoice is issued. Please note that advance payments do not influence the editorial decision regarding acceptance for publication. To request a proforma invoice, please contact the Accounts Receivable Team.

No, Payments are non-refundable once a paper has been accepted for publication. However, if the manuscript is withdrawn at the author’s request, the payment may be used as credit for future submissions.

No. APC payments cannot be refunded in the case of a retraction.

Yes, You may request a refund if your paper has been rejected, or you may choose to keep the amount as credit for your next submission.

If you are eligible for a refund, please send a request to the Accounts Receivable Team. Please include the relevant invoice number or manuscript ID in your email.