how much withholding from social security
Your employer is supposed to withhold 6.2% of your Social Security Wages (the Box 3 amount on your W-2), up to a maximum of $7,886.40 per taxpayer for tax year 2017. If one employer withheld too much Social Security tax, you won't be able to take a credit for the excess on your tax return. (TurboTax determines this by looking at your employer's EIN.