Understanding your CP133 notice

Notice details

Notice code

CP133

Category

Refund and adjustment

Severity tier

Tier 1 — Routine. Informational or administrative notice; no response typically required.

Governing law

§6213(b); §6402 (Internal Revenue Code sections)

Source

IRS.gov — Understanding Your IRS Notice

What this notice is

We made changes to your tax return because we believe there's a miscalculation on your return. As a result of these changes, there's an overpayment on your account.

Source: IRS.gov. Reproduced for reference. General information — not legal or tax advice.

What the IRS says to do

Read the notice carefully. It will explain the changes we made. Compare the figures on the notice with your tax return. If you agree with the changes we made, correct the copy of your tax return that you kept for your records. If you don't agree with the changes, contact us within 10 days from the date of your notice by calling the toll-free number listed on your notice or by mailing the completed contact stub with any correspondence or documentation. If you haven't already, you should receive a refund of the overpayment within four to six weeks if you owe no other taxes or debts we're required to collect. You don't need to take any further action.

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.

Official IRS reference

Read the official notice page on IRS.gov: https://www.irs.gov/individuals/understanding-your-cp133-notice

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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