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IRS CP518: Final Notice — Unfiled Return
Straight answer: A CP518 is the FINAL notice that the IRS has no record of your return. Next step if you stay silent: the IRS files a Substitute for Return (SFR) on your behalf — with zero deductions, zero credits, and maximum liability.
How many days do I have to respond to a CP518?
30 days from the date printed on the notice (not the day you opened it). Respond immediately. Once an SFR is assessed, you're fighting an inflated balance through collections instead of just filing a return.
Your response deadline is approximately — days from today.
What should I do right now?
- File the actual return now, even if you can't pay — the failure-to-file penalty (5%/month) dwarfs the failure-to-pay penalty (0.5%/month).
- If you already filed, send proof immediately.
- If you can't pay what the real return shows, set up a payment arrangement at filing.
The costly mistake people make with a CP518
Not filing because you can't pay. Filing without paying costs 10× less in penalties than not filing, and an SFR is the worst of all outcomes.
Do I need professional help with a CP518?
Yes if multiple years, business income, or you've received this for a year you thought was handled — SFR reversal is much harder than prevention.
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