Payment due date: a real date on every invoice

In short

Every tax invoice must carry a payment due date as a real calendar date. Payment terms such as "90 Days", "100% ADVANCE" or "120 Days PDC" can stay on the invoice, but they do not replace the date. Your accounts team works out the date when the invoice is raised. Credit notes carry no due date.

Why eInvoicing needs it

An eInvoice is read by software, not by a person. The software cannot turn "90 Days" into a date, so the eInvoice has a separate field that holds the date itself. The buyer's system uses it to schedule payment.

The UAE eInvoicing format makes the field compulsory. The due date must be present whenever there is an amount to pay. The only exceptions are credit notes and deemed supplies (goods or services you give away or use yourself, where nobody pays you). On a credit note, leave the date empty: nothing is due.

An invoice with only terms text and no date fails validation and does not reach your buyer.

What good looks like

Al Noor Trading LLC issues all of these invoices on 15 March 2027. This is how Calculus staff set the due date for each kind of term:

Terms printed today	Rule	Due date (YYYY-MM-DD)
30 Days	Invoice date + 30 days	2027-04-14
90 Days	Invoice date + 90 days	2027-06-13
Cash, cash on delivery (COD), "immediately upon receipt"	The invoice date	2027-03-15
100% ADVANCE (already paid)	The invoice date	2027-03-15
Cash against documents (CAD), "against B/L"	Expected payment date under the contract. Estimate it, for example invoice date + 21 days to present documents	2027-04-05
120 Days PDC (post-dated cheque)	The date written on the cheque	2027-07-13

Before and after, on one invoice to Gulf Spice Imports FZE:

Field	Before	After
Payment terms	"90 Days"	"90 Days" (optional)
Payment due date	Missing	2027-06-13

Where the answer depends on your contract, for example when payment is linked to delivery or acceptance, Calculus applies the expected payment date under that contract. Keep a short written rule for each kind of term so every invoice is dated the same way. Confirm with your tax advisor if your facts differ.

How to fix it in Tally

1. Turn on bill-wise tracking: press F11 (Features) and set Enable Bill-wise entry to Yes.
2. Open each customer ledger with Alt+G (Go To) > Alter > Ledger. Set Maintain balances bill-by-bill to Yes.
3. In the same ledger, fill Default credit period with the agreed credit days, for example 90 Days. Use 0 Days for cash customers.
4. When you raise a Sales voucher, check the credit period in the bill-wise details. Change it there for a one-off deal.
5. Make sure the due date prints on the invoice and reaches your eInvoicing export as a date field. If your invoice format shows only the terms, ask your Tally partner to add the due date (invoice date plus credit period).
6. For a post-dated cheque, enter the cheque date as the due date, not the credit days.

How to fix it in Excel or another system

Add a due date column next to the invoice date and calculate it, so nobody types it by hand.

Column	Format	Example
Invoice date	Date	2027-03-15
Credit days	Whole number	90
Payment due date	YYYY-MM-DD	2027-06-13

With the invoice date in B2 and the credit days in C2, use =B2+C2 and format the cell as yyyy-mm-dd. For cash and paid advances, put 0 in the credit days. Leave the due date empty on credit note rows.

If you use an ERP, ask your ERP partner to make the due date mandatory on every sales invoice, calculated from the customer's payment terms, and blank on credit notes.

Checklist

• Every tax invoice carries a due date as a real date (YYYY-MM-DD in upload files).
• Each customer has credit days recorded, including 0 for cash customers.
• Cash and paid-advance invoices use the invoice date.
• Post-dated cheque invoices use the cheque date.
• Credit notes leave the due date empty.

The law

• Peppol PINT AE specification, rule IBR-127-AE: Payment due date (IBT-009) must be present when the amount due for payment is greater than 0, except on credit notes and deemed supplies. PINT AE rule IBR-127-AE
• Peppol PINT AE credit note model, IBT-009 Payment due date. PINT AE IBT-009 (credit note)
• MoF UAE Electronic Invoicing Guidelines, section 12.1: the sample tax invoice shows a payment due date and payment terms as separate items. MoF PDF