IRS NOTICE REFERENCE
Understanding your letter 4800C
We’re proposing a change to your tax return.
General information only. Not legal or tax advice.
Notice details
- Notice code
- Letter 4800C
- Category
- Examination and audit
- Severity tier
- Tier 3 — Time-sensitive response. The notice carries a response deadline or may affect account standing if ignored.
- Governing law
- §7602 (Internal Revenue Code section)
- Statutory response window
- 30-day window — always confirm the exact deadline against the date printed on your notice.
- Source
- IRS.gov — Understanding Your IRS Notice
What this notice is
We’re proposing a change to your tax return.
Source: IRS.gov. Reproduced for reference. General information — not legal or tax advice.
What the IRS says to do
Review your tax return for the tax year in question. Review the "Changes to Your Return" section of the letter to decide if you agree or disagree with our proposed changes. If you don't agree with the changes, reply to us. Make sure to include supporting documentation. You can find a list of supporting items in the letter we sent. Complete and return the Response Form within 30 days from the date of the letter. For the fastest case resolution, reply using the Documentation Upload Tool: complete your letter (signed and dated) scan or take a photo of your letter showing if you agree or disagree complete the upload form submit your response complete your letter (signed and dated) scan or take a photo of your letter showing if you agree or disagree complete the upload form submit your response Reply to IRS You can also reply: Fax your information to the fax number in the letter using either a fax machine or an online fax service. Protect yourself when sending digital data by understanding the fax service’s privacy and security policies, or Mail using the envelope enclosed with the letter. Fax your information to the fax number in the letter using either a fax machine or an online fax service. Protect yourself when sending digital data by understanding the fax service’s privacy and security policies, or Mail using the envelope enclosed with the letter.
This is the IRS’s own guidance reproduced from the IRS notice page. It describes the IRS’s process — it is not legal or tax advice from TaxRiskOS.
Governing IRS procedure (Internal Revenue Manual)
The IRS’s own internal procedures for handling this notice type are documented in the Internal Revenue Manual:
- IRM 4.10.1 — 4.10.1 Overview of Examiner Responsibilities
- IRM 4.10.3 — 4.10.3 Examination Techniques
- IRM 4.13.1 — 4.13.1 Examination Audit Reconsideration Process
Reference to published IRS procedure. General information — not legal or tax advice.
Official IRS reference
Read the official notice page on IRS.gov: https://www.irs.gov/individuals/understanding-your-letter-4800c
Related tools
TaxRiskOS is workflow software for practitioners — it captures the notice, computes the deadline, surfaces the escalation tier, and builds a document checklist. It documents process; it does not give advice or draft responses.
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