On the paper
Locate the tax period, the current balance, and the date by which the IRS asks you to pay or respond.
Compare the balance on CP501 with the balance on the CP14 for the same year. The figure will usually be higher, and the difference is the penalty and interest that accrued between the two mailings. If the difference is larger than that, or if the tax period is one you have not seen before, the account has changed for a reason the reminder does not explain.
Find the date printed on your notice or letter. The paper notice and the current official IRS instructions control, even where this page differs.
Where this notice comes from
CP501 sits between the first bill and the harder collection notices. The IRS sends it when a balance from a CP14 or another assessment has gone unpaid through at least one notice cycle.
The value of CP501 is that it is still early. The balance is open, the account is not yet at the levy stage, and payment plans and other collection alternatives are handled by the ordinary service channels rather than by an appeals process. Every notice after this one narrows the choices.
The next reminder is CP503, and after that CP504 warns of levy. A taxpayer who intends to resolve the balance is better served acting on CP501 than waiting to see what the following notice says.
General next steps
- Compare the notice against your return, your prior payments, and any earlier IRS correspondence for that year.
- If you agree with the amount, review the official payment options and decide whether you can pay in full.
- If you disagree, use the contact instructions on the notice rather than sending records through any website.
Timing
The IRS page for CP501, checked September 10, 2026, gives no general period and refers to the due date shown on the notice. The date printed on the notice controls; do not calculate a deadline from this page.
What CP501 does not mean
A reminder is not an enforcement action. CP501 does not levy anything, does not file a lien, and does not start the Collection Due Process clock. It also does not mean the IRS has reviewed anything you sent since the first bill. Correspondence and notices cross in the mail routinely.
What this page cannot tell you
This page cannot verify your IRS account, your payment history, or whether the balance the IRS shows is accurate.
How do I respond to an IRS collection notice?
Read the paper notice first. Identify the letter code, the assessed balance, and any date printed on it. Read How do I respond to an IRS collection notice?.
IRS collections
This letter involves an unpaid IRS balance or a collection action. Read IRS collections.
Official sources
If anything on this page differs from your notice or from current IRS instructions, follow the notice and the IRS.
Common questions
What happens if I ignore a CP501?
The IRS continues the notice sequence. CP503 generally follows, then CP504, which warns of levy. Penalties and interest continue to accrue throughout. Ignoring the reminders does not pause the account.
Can I set up a payment plan at the CP501 stage?
The IRS publishes payment plan options and the eligibility rules for each. Whether a plan is available depends on the amount, the tax years involved, and whether required returns have been filed. The notice and the IRS payment pages give the current application routes.
Why is the balance higher than the first notice showed?
Failure-to-pay penalty and interest accrue between mailings, so the reminder usually shows a larger figure than the original bill for the same year. The notice breaks the current total into its parts.