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Published:   |   Last Updated: April 24, 2023

Notice CP521 – Monthly Installment Agreement Payment Reminder (SB/SE Notice)

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Notice Overview

This monthly notice is sent to remind you that your installment agreement payment is due.

This notice or letter may include additional topics that have not yet been covered here. Please check back frequently for updates.

What does this mean to me?

This notice tells you the amount you need to pay, when it is due, and a summary of your agreement with the remaining balance owed. The notice also details:

  • Options available for making the payment;
  • Consequences of not making the payment;
  • Information on penalty and interest, including how to request removal or reduction of penalties; and
  • Online Payment Agreement options including due date changes, requesting the payoff amount, and setting up direct debit payments.

How did I get here?

You have a tax balance and entered into a payment plan (installment agreement).  This notice advises that you have a payment due on a payment plan with the IRS.

View Notice Online:

View your federal tax records and manage your communication preferences online

Sign in to your Online Account to:

  • Make payments
  • Go paperless for certain notices
  • Get email notifications for new notices

What are my next steps?

To keep your payment plan in good standing you need to make your payment by the due date. See Payments for options to make a payment.

If you would like to convert your existing Installment Agreement to a Direct Debit Installment Agreement where your  payment would be automatically deducted from your bank account you can request the revision of your payment plan via the online payment agreement page on IRS.gov.

If you are no longer able to make you installment agreement payments, you should contact the IRS at the number provided in the notice. You can also request a change to your payment amount via the online payment agreement page on IRS.gov. If you are unable to continue with an approved payment plan, review the collection alternatives.

If you default, the installment agreement may be terminated, and the IRS may begin taking enforcement action or you may have to pay a fee to reinstate the agreement.  You have the right to appeal the default or termination of your payment plan through the Collection Appeals Program.

Where can I get additional help?

Understanding your Notice or Letter

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Browse common tax issues and situations at TAS Get Help

If you still need help

The Taxpayer Advocate Service (TAS) is an independent organization within the IRS that helps taxpayers and protects taxpayers’ rights. We can offer you help if your tax problem is causing a financial difficulty, you’ve tried and been unable to resolve your issue with the IRS, or you believe an IRS system, process, or procedure just isn’t working as it should. If you qualify for our assistance, which is always free, we will do everything possible to help you.

Visit www.taxpayeradvocate.irs.gov or call 1-877-777-4778.

Low Income Taxpayer Clinics (LITCs) are independent from the IRS and TAS. LITCs represent individuals whose income is below a certain level and who need to resolve tax problems with the IRS. LITCs can represent taxpayers in audits, appeals, and tax collection disputes before the IRS and in court. In addition, LITCs can provide information about taxpayer rights and responsibilities in different languages for individuals who speak English as a second language. Services are offered for free or a small fee. For more information or to find an LITC near you, see the LITC page on the TAS website or Publication 4134, Low Income Taxpayer Clinic List. This Publication is also available online at www.irs.gov or by calling the IRS at 1-800-829-3676.


Where am I in the tax system?

CP521 – Monthly Installment Agreement Payment Reminder