Retirement tax questions

The penalties are based on your total tax liability not your estimated tax voucher amounts.   I agree with increasing the vouchers accordingly so you do not have any surprises.   You can use the Tax Caster throughout the year.

To determine whether you need to make quarterly estimates, answer these questions:

1. Will you owe less than $1,000 in taxes for the tax year after subtracting your federal income tax withholding (including estimated tax payments made) from the total amount of tax you expect to owe this year? If so, you're safe—you don't need to make estimated tax payments.
2. Do you expect your federal income tax withholding (including estimated tax payments made) to amount to at least 90 percent of the total tax that you will owe for this tax year? If so, then you're in the clear, and you don't need to make estimated tax payments.
3. Do you expect that your income tax withholding (including estimated tax payments made) will be at least 100 percent of the total tax on your previous year's return? Or, if your adjusted gross income (2023 Form 1040, line 11) on your tax return was over $150,000 ($75,000 if you're married and file separately), do you expect that your income tax withholding will be at least 110 percent of the total tax for the previous year? If so, then you're not required to make estimated tax payments.

If you answered "no" to all of these questions, you must make estimated tax payments using Form 1040-ES. To avoid a penalty, your total tax payments (estimated taxes plus withholding) during the year must satisfy one of the requirements we just covered.