CP45: We Couldn't Apply Your Overpayment to Next Year's Estimated Taxes

Why you might get this

• You asked the IRS to apply your overpayment (money you paid above what you owed) to your next year's estimated taxes.
• The IRS could not apply that overpayment the way you requested.
• Something changed on your tax return that affected the amount available to carry forward.

The deadline

This notice is mainly a confirmation of how the IRS handled your overpayment, so there isn't a formal response deadline in the usual sense. Still, read your notice right away and follow any timing printed on it. The practical urgency is about adjusting your current year's estimated tax payments soon so you don't accidentally underpay.

This notice doesn't carry a fixed response deadline, but it still deserves attention — see what to do below.

What to do

1. Read your notice carefully to understand why the IRS couldn't apply your overpayment and what steps they suggest.
2. Update your own copy of your tax return so your records match the IRS's numbers.
3. Adjust your current year's estimated tax payments so you don't end up underpaying. Form 1040-ES and Publication 505 can help you recalculate.
4. If you're not sure what changed on your return, call the phone number printed on your notice for an explanation.
5. If you owe a remaining balance, look into your payment options, including a payment plan (installment agreement).

What happens if you ignore it

This notice is your confirmation, so the IRS won't send another one about how the overpayment was applied. But if you don't adjust your estimated payments, you could underpay your taxes and owe an underpayment penalty later. Any remaining balance you owe can keep growing with penalties and interest until you pay it.

If you can't resolve the issue after calling the IRS, you may qualify for free help from the Taxpayer Advocate Service (TAS) or a Low Income Taxpayer Clinic. You can also authorize someone, like a tax pro, to represent you before the IRS.

A CP45 notice means the IRS could not apply your overpayment to next year's estimated taxes the way you requested. An overpayment is money you paid above what you actually owed, either through paycheck withholding or estimated payments. Normally you can choose to have that extra amount refunded or carried forward, but in this case the IRS couldn't carry it forward as planned.

Start by reading your notice closely. It explains why the overpayment couldn't be applied and may list next steps. Update your own copy of your return so your records match the IRS's numbers.

The most important thing to do is adjust your current year's estimated tax payments. If your carryforward is smaller than you expected, you could underpay and face a penalty. Form 1040-ES and Publication 505 can help you recalculate. If you owe a remaining balance, look into payment options like an installment agreement.

Not sure what changed? Call the number on your notice — the IRS can explain exactly what happened.

This notice is your confirmation, so no follow-up letter is coming. Solace can keep an eye on your IRS account so you always know where things stand.