IRS NOTICE REFERENCE
Understanding your CP45 notice
We couldn't apply your overpayment to your next year’s estimated taxes like you asked.
General information only. Not legal or tax advice.
Notice details
- Notice code
- CP45
- Category
- Refund and adjustment
- Severity tier
- Tier 1 — Routine. Informational or administrative notice; no response typically required.
- Governing law
- §6213(b); §6402 (Internal Revenue Code sections)
- Source
- IRS.gov — Understanding Your IRS Notice
What this notice is
We couldn't apply your overpayment to your next year’s estimated taxes like you asked.
Source: IRS.gov. Reproduced for reference. General information — not legal or tax advice.
What the IRS says to do
Read your notice carefully - it explains why we couldn't apply your overpayment and may include next steps. Update your own copy of your tax return for your records. Adjust the amount of your current year's estimated tax payments so you don’t end up underpaying.
This is the IRS’s own guidance reproduced from the IRS notice page. It describes the IRS’s process — it is not legal or tax advice from TaxRiskOS.
Official IRS reference
Read the official notice page on IRS.gov: https://www.irs.gov/individuals/understanding-your-cp45-notice
Related tools
TaxRiskOS is workflow software for practitioners — it captures the notice, computes the deadline, surfaces the escalation tier, and builds a document checklist. It documents process; it does not give advice or draft responses.
Check this notice’s deadline (free tool)