What this notice is about
If you received a CP521K Notice, the IRS is reminding you that you have an installment payment due. Send your payment immediately.
View this notice and manage your communication preference online
Sign in to your online account to:
- View and download this notice
- Go paperless for certain notices
- Get email notifications for new notices
What you need to do
- Read your notice carefully. It's a reminder to send in your monthly payment.
- Pay by the due date. Go to the payments page to find out more about your payment options.
Frequently asked questions
Your monthly installment agreement payment is due to us by a specific date.
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.
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.
If you have any questions, call us at the number at the top of the notice. A customer service representative will assist you.
Need help?
- You can authorize someone to represent you before the IRS or inspect and/or receive confidential tax information.
- You may be eligible for free help from the Taxpayer Advocate Service (TAS).
- See if you qualify for help from a Low Income Taxpayer Clinic.
- You can request a copy of your notice or letter in Braille or large print.
- If you can’t find what you need online, call the telephone number on your notice or letter.