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In the IRS’s own words · not reviewed by VALID
CP521 notice explained, in the IRS’s own words
If you received a CP521, CP521 (SP) or CP621 Notice, the IRS is reminding you that you have an installment payment due. Send your payment immediately.
Read the full CP521 page on irs.gov ↗
What this notice is about
If you received a CP521, CP521 (SP) or CP621 Notice, the IRS is reminding you that you have an installment payment due. Send your payment immediately.
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
What is the notice telling me?
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, call us at the number at the top of the notice. A customer service representative will assist you.
Reference tools
- Publication 1, Your Rights as a Taxpayer
- Full list of tax forms and instructions
Need help?
- You can authorize someone to contact the IRS on your behalf.
- If you can’t find what you need online, call the IRS number on your notice or letter. If you didn’t receive a letter or notice, use telephone assistance.
- If you can't resolve the penalty on your own, contact Taxpayer Advocate Service, an independent organization within IRS.
What to do next
- Write down the date on the letter today.
- Look the number up on irs.gov yourself. Don’t trust a link or phone number from anyone else.
- If it says you owe money or proposes changes to your return, take it to a licensed CPA, EA or tax attorney before that date.
Not advice. Not a filing. Verify with a licensed professional. Rules change by year and facts.