What Is an IRS Notice CP210 and How to Respond?

An IRS Notice CP210 is a formal communication from the Internal Revenue Service about a change made to your tax account for a specific year. This notice is an informational update, not an audit, that the IRS is required to send whenever it adjusts a filed return. The adjustment could result in a refund, a balance due, or no change to your overall tax liability. While it can apply to any taxpayer, this notice is frequently used to communicate adjustments to business tax accounts, particularly concerning employment taxes.

Common Reasons for Receiving a CP210 Notice

A frequent reason for receiving a CP210 is the application of an overpayment from one tax period to a balance due in another. For instance, if you overpaid your 2024 taxes, the IRS might automatically apply that credit to an outstanding tax debt from 2023 instead of issuing a refund. This reallocation of funds between tax years is a common administrative action detailed in the notice.

Another common scenario involves adjustments to your estimated tax payments. If the IRS records of your quarterly payments do not match the amount you claimed on your Form 1040, a CP210 will be issued to reflect the discrepancy. This could happen due to a misapplied payment, a late payment, or a data entry error. The notice will correct your account to show the actual payments received and recalculate your tax liability.

The notice may also assess penalties for late filing or payment. For businesses, a CP210 is commonly issued for adjustments to employment taxes, such as those filed on Forms 941 or 944. It can include penalties for failing to deposit these taxes correctly or on time, which are often accompanied by interest charges detailed in the notice.

Required Information for Your Response

The first step upon receiving a CP210 is to compare the notice with your original tax return for the year in question. Place the notice and your tax return side-by-side to verify the adjustments. If you agree with the IRS’s correction, no further action or response is necessary; you would simply pay any amount due by the specified deadline.

If you disagree with the adjustments, you must gather specific documentation to support your position before contacting the IRS. You will need a copy of the CP210 notice itself, a complete copy of your tax return for the relevant year, and any supporting documents that substantiate your original figures.

The type of supporting documents needed depends on the adjustment. If the IRS adjusted your reported tax payments, gather canceled checks or bank statements. If the change relates to tax withholding, you will need your Form W-2 or 1099s. For businesses disputing employment tax adjustments, documents would include payroll records and proof of federal tax deposits. For changes to credits or deductions, you need receipts or other records that validate the amounts you claimed.

How to Formally Respond to the IRS

Once you have gathered all necessary documentation, you can respond to the IRS by telephone or mail. The appropriate phone number and mailing address are listed directly on the CP210 notice. The notice also contains important reference numbers for your case, so be sure to keep it.

For a telephone response, call the number provided on the notice. Before you call, have your CP210 notice, tax return, and all supporting documents organized. When you speak with an IRS representative, be prepared to state your name, Social Security Number or Taxpayer Identification Number, the tax year, and the notice number (CP210). You should then explain why you disagree with the adjustment and be ready to reference your specific documents.

Alternatively, you can respond by mail by writing a formal letter explaining your disagreement. Your letter must include your full name, taxpayer identification number, and the tax year, and you should reference the CP210 notice. Clearly outline each disputed item and provide a brief explanation for why you believe the original return was correct. Attach copies—never the originals—of your supporting documents and mail the complete package to the address shown on the notice. The IRS will then review your information and either reverse the change or provide a more detailed explanation in a subsequent notice.