Preserve every page
Keep the envelope, attachments and both sides of every page. Work from a copy.
Private, browser-based first look
What does this IRS or California FTB letter mean?
Enter the notice identifier—not your name, Social Security number, account number or dollar amount—to get a plain-English orientation, urgency cues and the official agency source.
Source review: October 30, 2026 · Results are educational, not a substitute for the actual notice or professional advice.
Notice lookup
Start with the agency and printed identifier.
Try an example:
The first five moves
Useful self-help before calling anyone.
Circle the dates
Identify the notice date, response date, payment date and any appeal or petition deadline.
Compare the records
Match the agency’s statement to the filed return, payment history and relevant source documents.
Use official channels
Verify the notice through IRS.gov, an IRS Online Account, FTB.ca.gov or MyFTB—not a number found in an advertisement.
Keep a response log
Record calls, uploads, fax confirmations, certified-mail tracking and copies of what you sent.
Common federal correspondence
What the most-searched IRS notice numbers generally signal.
The printed notice controls. These summaries help you identify the category and the next question to ask.
CP14: balance due
The IRS uses CP14 when it says unpaid tax is due. Compare the amount and payment history, then follow the notice to pay, arrange payments or dispute the balance by the stated date.
CP2000: information mismatch
This is a proposed change—not a bill—based on a mismatch between the return and third-party information such as Forms W-2 or 1099. Review each item and respond by the printed date whether you agree or disagree.
CP504: collection is escalating
This says an unpaid balance remains and warns of levy action against a state tax refund. Do not wait for the next letter to start resolving the balance or disputing the account.
CP90 or CP297: hearing rights
These are final levy notices that include the right to request a Collection Due Process hearing. Treat the response date as rights-sensitive.
CP3219A: statutory notice of deficiency
This explains a proposed increase and the right to challenge it in U.S. Tax Court. Sending more information to the IRS does not extend the petition deadline shown on the notice.
5071C, 4883C or 5747C: identity verification
These letters ask the taxpayer to verify identity and the return. The route differs: online/phone, phone, or an in-person appointment. Use only the instructions and official channels tied to the letter.
California FTB letters
A DLN identifies the letter. A paragraph code may explain the change.
Many FTB letters carry an alphanumeric document locator number at the top center. On a Notice of Tax Return Change, one or more shorter alphanumeric codes can appear at the end of individual paragraphs. Those codes identify why FTB changed the return and what records to review.
FTB DLN
Use it to identify the correspondence on the official FTB letter-help page or when communicating with FTB. Do not treat the characters alone as a complete explanation of the tax issue.
Return-change code
Examples include AA for an adjusted California AGI amount, AC for an incomplete return processed with available information, and OA/OB for refund or balance-due arithmetic changes. Always read every code on the notice together.
Primary sources and next steps
Verify the result at the agency—or define the representation question.
- IRS: Understanding your notice or letter
- IRS: Ways to distinguish genuine contact from scams
- California FTB: Letters and DLN help
- California FTB: Notice of Tax Return Change code table
- IRS, Taxpayer Advocate and FTB telephone directory
- IRS representation by an Enrolled Agent
Government pages can change. The actual notice, current agency instructions and applicable deadlines control.