You can use the IRS Tax Withholding Estimator to estimate the extra amount you should withhold. Divide the amount among your remaining pay periods for the current year and note that amount to Form W-4 Line 4(c). It will add to your Federal withholdings on your W-2. If you have too much withheld, it will be refunded on your tax return.
TurboTax Expert Assist
Get answers to all your tax questions
Our experts are available on-demand, no appointment needed. Get help all year long with TurboTax Expert Assist.