Understanding your CP521 Notice
This notice is to remind you that you have an installment agreement payment due. Please send your payment immediately.
Printable samples of this notice (PDF)
Tax publications you may find useful
- Publication 1, Your Rights as a Taxpayer
- Notice 746, Information About Your Notice, Penalty and Interest
- Find a copy of any necessary tax forms and instructions
How to get help
Calling the 1-800 number listed on the top right corner of your notice is the fastest way to get your questions answered.
You can also authorize someone (such as an accountant) to contact the IRS on your behalf using this Power of Attorney and Declaration of Representative (Form 2848).
Or you may qualify for help from a Low Income Taxpayer Clinic.
What you need to do
- Read your notice carefully — it is a reminder to send in your monthly payment.
- Make your payment by your due date. Go to the payments page to find out more about your payment options.
You may want to...
- Download copies of the following materials that may be helpful:
- Call 1-800-TAX-FORM (1-800-829-3676) to have forms and publications mailed to you.
Answers to Common Questions
What is the notice telling me?
This notice is telling you that you that your monthly installment agreement payment is due to us by a specific date.
What do I have to do?
Pay the amount due shown on the notice. Mail us your payment in the envelope we sent you. Include the bottom part of the notice to make sure we correctly credit your account.
What happens if I don't pay?
If you don't send us a payment, the interest and penalties you'll have to pay will increase and you could default on your installment agreement.
Who should I contact?
If you have any questions about the notice, call us at the number printed at the top of the notice. A customer service representative will assist you.
Understanding your notice
Reading your notice
Your notice may look different from the sample because the information contained in your notice is tailored to your situation.
Notice CP521, Page 1
Notice CP521, Page 2
Notice CP521, Page 3