W4 selection

The new versions of the W-4 no longer have you claim Filing Status (Single, Married Filing Joint, etc.) and the number of exemptions (0, 1, 2, etc.).  Instead the IRS wants taxpayers to estimate what has been earned to date from all sources (multiple jobs, retirement, self-employment, etc.) and how much has been paid in through withholding to calculate what the federal withholding should be for the rest of the year.  

TurboTax has two calculators to help you make these decisions.  

TurboTax's W-4 Calculator

TurboTax's Tax Caster tax calculator

You can then use the results from the calculators to complete a new W-4 form for either employer.