IRS CP503: what it means and what to do
This is your second reminder that you have an unpaid balance on one of your tax accounts, because the IRS hasn't received your payment or a response to earlier notices. This summary is drawn from the IRS page for the CP503, last checked on October 13, 2026.
Why you received a CP503
- The IRS hasn't received payment or a response to previous notices about this balance
What to do
- Read the notice for the amount owed, due date, and payment options
- Pay the amount by the due date shown
- If you can't pay in full, apply for a payment plan
- If you disagree, call the toll-free number on the notice
Deadline: Pay the full balance by the due date on your notice to avoid additional penalties and interest
If you disagree, or do not respond
Contact the IRS right away to discuss it with a customer service representative. If you already took corrective action, still call so your account reflects it. You can also request an appeal under the Collection Appeals Program before collection action.
The IRS may file a Notice of Federal Tax Lien if it hasn't already, a public claim on your current and future assets that can affect your ability to get credit.
Get your records together first
Most notices come down to matching what the IRS has on file against your own records. Before you reply, pull the return the notice refers to, the bank statements and income forms for that year, and any payment confirmations. If your books are reconciled to the bank, that comparison takes minutes instead of days.
Source and verification
IRS: Understanding your CP503 notice →
Last verified against that page on October 13, 2026. This is general information, not advice for your situation. The notice itself is the authority on your amounts and dates. Talk to a CPA or enrolled agent if the amounts are large or you are unsure.
Related
- All IRS notices explained
- IRS CP2000 — The IRS is proposing changes to your tax return because income or payment information it received from third parties does not match what you reported.
- IRS CP14 — The IRS says you owe money on unpaid taxes.
- IRS CP501 — This is a reminder that you still owe a balance on one of your tax accounts.
- IRS CP504 — This is a Notice of Intent to Levy under Internal Revenue Code section 6331(d) and a final reminder that the IRS may levy your wages, bank accounts, or state tax refund for an unpaid balance.
- IRS LT11 — The IRS has not received payment for overdue taxes and intends to seize your property or rights to property.
- IRS CP90 — The IRS intends to levy (seize) certain assets to collect unpaid taxes.
- Find an accountant — for help responding.
Frequently asked questions
What is an IRS CP503 notice?
This is your second reminder that you have an unpaid balance on one of your tax accounts, because the IRS hasn't received your payment or a response to earlier notices.
How long do I have to respond to a CP503?
Pay the full balance by the due date on your notice to avoid additional penalties and interest Check the date printed on your own notice, which is the one that applies to you.
What happens if I ignore a CP503?
The IRS may file a Notice of Federal Tax Lien if it hasn't already, a public claim on your current and future assets that can affect your ability to get credit.
What if I disagree with the CP503?
Contact the IRS right away to discuss it with a customer service representative. If you already took corrective action, still call so your account reflects it. You can also request an appeal under the Collection Appeals Program before collection action.
What is the notice telling me?
It is your second reminder about an unpaid balance.
How much time do I have?
Until the due date on the notice, to avoid extra penalties and interest.
What happens if I don't pay or respond?
The IRS may file a tax lien, which can affect your ability to get credit.
What if I don't agree or already took action?
Call the number on your notice and the IRS will try to assist you.
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Authoritative sources
US tax rules change every filing season. Always verify the current position with the official sources below before filing.
- IRS — irs.govInternal Revenue Service. Forms, publications, due dates, and current-year thresholds for federal income tax, payroll tax, and 1099 reporting.
- IRS — Forms & InstructionsCanonical PDF forms (W-4, W-9, 1099-NEC, 1040-ES, 941, 940, W-2, W-3) with current-year instructions.
- SSA — Business Services OnlineSocial Security Administration portal for W-2 / W-3 e-filing, EIN verification, and AccuWage validation.
- Streamlined Sales Tax — streamlinedsalestax.orgMulti-state Streamlined Sales and Use Tax Agreement (SSUTA) — registration in 24 SST member states with one application.
- Tax Foundation — Sales Tax & NexusIndependent state-by-state research on sales tax rates, economic nexus thresholds, and franchise / margin tax structures.
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