IRS Notice CP45: Overpayment couldn't go to next year
Quick answerYou asked to apply your overpayment to next year's estimated tax, but the IRS couldn't apply all of it — usually because your overpayment was smaller than expected.
Letter / noticeCP45
MeaningOverpayment couldn't go to next year
Action needed?Yes — see steps
What happens next
Make up any shortfall in your estimated payments for the new year.
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What you should do
- Check how much was actually applied
- Adjust your next estimated payment to avoid a penalty
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 CP45 mean?
You asked to apply your overpayment to next year's estimated tax, but the IRS couldn't apply all of it — usually because your overpayment was smaller than expected.
What should I do?
Check how much was actually applied Adjust your next estimated payment to avoid a penalty
How long does it take?
Make up any shortfall in your estimated payments for the new year.
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.