CASS Cheat Sheet 2026

The 30 highest-yield CASS facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. USPS charges a Move Update non-compliance surcharge on which class of mail? → Both First-Class Mail and Marketing Mail
2. Which USPS publication defines the technical specifications for the Delivery Point Barcode? → Domestic Mail Manual (DMM) Section 708
3. In the context of CASS certification, what is the most important consideration when implementing presort & mail preparation? → Ensuring alignment with established standards, stakeholder needs, and best practices
4. In POSTNET coding, each digit is represented by a combination of how many tall and short bars? → 2 tall, 3 short
5. Why is annual certification required? → Maintain postal compliance
6. What is the maximum acceptable skew angle for a POSTNET barcode printed on a mail piece per USPS standards? → 5 degrees
7. What is the benefit of complying with USPS addressing standards? → Better deliverability and discounts
8. An address listed as '100 N. Oak Street Northwest' should be standardized to which USPS format? → 100 N Oak St NW
9. What is the consequence of using uncertified software? → Mail rejection or lost discounts
10. How are ambiguous addresses handled? → Use extra data to clarify
11. A carrier route code beginning with 'R' identifies which type of route? → Rural route
12. In CASS processing, what is the purpose of the 'LACS Link' component? → Convert rural route addresses to street-style addresses
13. An address record fails DPV confirmation but passes ZIP+4 coding. What is the most likely reason? → The specific primary number does not exist in the USPS delivery point database
14. Which scenario would cause a POSTNET barcode to fail USPS barcode quality standards? → The barcode is located 0.5 inches from the bottom edge
15. Which USPS endorsement instructs the postal service to return undeliverable mail and provide the new address if available? → ADDRESS SERVICE REQUESTED
16. Why is CASS certification important for mailers? → Ensures USPS compliance
17. For USPS acceptance of automated-rate mailings, how current must the CASS processing date on Form 3553 be? → Within 180 days of mailing
18. A record returns a CASS footnote of 'G'. What does this indicate? → The address matched a primary number that falls within a valid range
19. Which of the following best describes a key competency required for address hygiene & data quality in CASS practice? → Strong analytical skills combined with effective communication and ethical judgment
20. A mailer prints a DPBC using the ZIP Code, plus-4 code, and delivery point. If the ZIP+4 is unknown, what fallback is permitted for POSTNET? → Print the 5-digit ZIP barcode only (32 bars)
21. When CASS-certified software cannot match an address, what should the mailer do to maintain automation rate eligibility? → Remove unmatched records from the mailing or correct the addresses before re-processing
22. For a standard street address at 450 Main St, what two digits form the POSTNET delivery point? → 50
23. When processing a mailing list with NCOALink, what does a Type 2 move indicate? → An individual at an address moved, but other residents remain
24. How many digits can a USPS-assigned Mailer ID (MID) contain in the Intelligent Mail barcode? → 6 or 9 digits
25. What minimum ZIP+4 coding accuracy percentage must CASS-certified software achieve on USPS test files? → 98%
26. What is the significance of the CASS 'cycle' date stamped on Form 3553? → It identifies which USPS address file vintage was used during processing
27. What does a high undeliverable-as-addressed (UAA) rate primarily indicate about a mailing list? → The list contains outdated or inaccurate address data
28. Which tool does USPS provide to help mailers identify and correct addresses that are likely to become undeliverable? → Address Element Correction (AEC)
29. Which CASS output indicator confirms that a specific address exists in the USPS Residential Delivery Indicator (RDI) file? → RDI flag field
30. Under USPS standards, what is the minimum bar height for a POSTNET barcode full bar printed on a mail piece? → 0.125 inches