This year, Paula and Simon (married filing jointly) estimate that their tax liability will be $218,000. Last year, their total tax liability was $182,000. They estimate that their tax withholding from their employers will be $188,800. Are Paula and Simon required to increase their withholdings or make estimated tax payments this year to avoid the underpayment penalty? If so, how much?

1. Yes

2. $7,400

Explanation:

Basic Rules For Estimated Tax For Individuals

Any individual who has estimated tax for the year of $1,000 or more and  whose withholding does not equal or exceed the “required annual payment” must make quarterly payments. Otherwise, a penalty may be assessed. The required annual payment is the smaller of the following amounts:  

1.Ninety percent of the tax shown on the current year's return.  

2.One hundred percent of the tax shown on the preceding year's return (the return must cover the full 12 months of the preceding year). If the AGI on the preceding year's return exceeds $150,000 ($75,000 if married filing separately), the 100% requirement is increased to 110%.

Are Paula and Simon required to increase their withholdings or make estimated tax payments this year to avoid the underpayment penalty?

Following the basic rules above, yes, Paula and Simon have to increase their withholdings or make estimated tax payments this year to avoid the underpayment penalty.

If so, how much?

Amount of income tax liability = $218,000

In general, taxpayers must pay at least 90 percent of their tax bill during the year to avoid an underpayment penalty when they file.

Therefore Minimum estimated payments-90% : $218,000 * 0.9 = $196,200

110% of the preceding year's tax: $182,000 * 1.10 = $200,200

According to the basic rules the required annual payment is the smaller which is $196,200.

Tax withholding from their employers = $188,800

Estimated tax payments required = $196,200 - $188,800 = $7,400