When you have two jobs, accurately completing your W-4 forms is crucial to avoid underpayment penalties or paying too much in taxes.
The W-4 form, "Employee's Withholding Certificate," tells your employer how much federal income tax to withhold from your paycheck. Having two jobs complicates this, as withholding calculations are usually based on a single income . You would complete step 2 on the Form W-4 if you have a second job. The IRS also has a withholding estimator that is fairly accurate in predicting how much tax liability you might have. This calculator can be found at on the IRS website. I have posted the link below. There is also a worksheet on page 3 of form W-4 for manually calculating your projected income tax liability. If you follow the steps on Form W-4 you should have enough withholding to cover your taxes from your jobs and any other taxable income you might have. https://www.irs.gov/individuals/tax-withholding-estimator
