IRS Notice CP521: Installment agreement payment reminder
Quick answerA monthly reminder of the payment due under your installment agreement, with your remaining balance.
Letter / noticeCP521
MeaningInstallment agreement payment reminder
Action needed?Yes — see steps
What happens next
Pay by the date shown to keep the agreement in good standing.
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What you should do
- Make the payment on time
- Consider direct debit to avoid missed payments
Scam check: the IRS first contacts you by mail. Use only the phone numbers printed on your letter or on IRS.gov — never ones from a text, email or unofficial site.
Frequently asked questions
What does IRS Notice CP521 mean?
A monthly reminder of the payment due under your installment agreement, with your remaining balance.
What should I do?
Make the payment on time Consider direct debit to avoid missed payments
How long does it take?
Pay by the date shown to keep the agreement in good standing.
Sources
- IRS: Understanding your IRS notice or letter
- IRS: Get Transcript
- Taxpayer Advocate Service (independent help inside the IRS)
Written by the editorial team and checked against the official sources above. See our editorial policy.
By the TranscriptCodes Editorial Team · Last reviewed 2026-11-12.