Underpayment penalty

Did you fill out form 2210?

If Turbo Tax calculates a penalty on 1040 line 38…..You might be able to eliminate it or at least reduce it.  You can go to Federal Taxes tab or Personal tab, under Other Tax Situations and select Start by the Underpayment Penalties. You will answer a series of questions that may reduce or eliminate the penalty. Or you can elect to have the IRS figure the penalty for you.  It's form 2210.

It's under

Federal or Personal (for Home & Business Desktop)

Other Tax Situations

Additional Tax Payments

Underpayment Penalties - Click the Start or update button

The IRS has some safe harbor rules. Meet any one of them, and there will be no federal underestimation of tax penalties.

There will be no 2026 federal penalties for not prepaying enough taxes during the year if withholding and

1. timely estimated tax payments equal or exceed 90% of your 2026 tax or
2. timely estimated tax payments equal or exceed 100% of your 2025 tax (110% if your 2025 adjusted gross income was more than $150K) or
3. the balance due after subtracting taxes withheld from 90% of your 2026 tax is less than $1,000 or
4. your total taxes are less than $1,000

The second one is the easiest to meet because if you complete your 2025 taxes by around the end of March,

you'll know what must be paid in - 1/4 of the required amount each period, which generally have due dates of 4/15, 6/15,9/15 and 1/15 of the following year. If you have any control over your withholding, you may be able to increase it later in the year to make up for any deficiency. The IRS rules state that you can deem 1/4 of your annual withholding to be withheld each period.  However, estimated tax payments only count for that period if paid on or before the due date. 

state laws differ