N.J. Admin. Code § 18:2-4.5
If the postmark on the envelope or wrapper containing the documents or payments is made by the United States Postal Service, to be timely such postmark must bear a date stamped by the United States Postal Service which is within the prescribed period or on or before the prescribed date for filing or paying (including any extensions of time granted for filing or paying). If the postmark stamped by the United States Postal Service on the envelope or wrapper does not bear a date which falls within such prescribed period or on or before such prescribed date for filing or paying, the document or payment will not be considered to be timely filed or paid, regardless of when the envelope or wrapper was deposited in the mail. Accordingly, the sender assumes the risk that the envelope or wrapper will not bear a postmark date stamped by the United States Postal Service within the prescribed period or on or before the prescribed date for filling or paying (including any extensions of time granted for filing or paying). See 18:2-4.9 with respect to the use of registered mail or certified mail to avoid this risk. Furthermore, if the postmark made by the United States Postal Service on the envelope or wrapper containing the document or payment is not legible, the provisions of 18:2-4.6 shall apply.
Example 1: 3rd Quarter Sales and Use Tax Return
| Due Date: | October 20 |
| Postmarked: | October 20 |
| Received by Division of Taxation | October 24 |
The return would be considered timely filed.
Example 2: 3rd Quarter Sales and Use Tax Return
| Due Date: | October 20 |
| Postmarked: | October 21 |
| Received by Division of Taxation | October 26 |
The return would be considered filed on October 26.
N.J. Admin. Code § 18:2-4.5