---
title: What Are IRS Letter Codes? Your 2026 Guide | TaxTruce
url: https://taxtruce.com/answers/what-are-irs-letter-codes
updated: 2026-10-29
---

# What are IRS letter codes?

Updated October 8, 20262 sourcesTaxTruce team[Fact checked](/editorial-standards)

The short answer

The code in the top right corner, like CP14 or CP504, tells you what the notice is about. The IRS has a page for each common notice that explains what to do. The Taxpayer Advocate Service also has a notice lookup.

## Words to know

[CP504](/glossary)
:   An IRS notice of intent to levy. It is a reminder before the IRS starts to levy.

[Taxpayer Advocate Service (TAS)](/glossary)
:   An independent office inside the IRS that helps people with problems they can't fix on their own.

## Sources

1. [IRS: Understanding your CP14 notice](https://www.irs.gov/individuals/understanding-your-cp14-notice)
2. [Taxpayer Advocate Service](https://www.taxpayeradvocate.irs.gov/)

Run the numbers with our [free tax tools](/tools), like the penalty and payment plan math.