Taxable Income

Taxable income is the figure that drives federal and state income tax withholding each pay period. It's calculated from gross pay minus pre-tax benefit deductions, and it's reported in different ways on the W-2 for federal income tax, Social Security, Medicare, and state income tax (which sometimes use slightly different bases). Getting taxable income wrong creates W-2 errors that cascade into employee tax filing problems and IRS notices.

What Counts as Taxable Income for Payroll

Wages and salary, overtime, bonuses, commissions, vacation payouts, severance, taxable fringe benefits (group term life over $50,000, personal use of company vehicle, club memberships), and equity compensation when it vests or is exercised.

What's Excluded from Taxable Income

Pre-tax 401(k) contributions, HSA contributions, FSA contributions, qualified transit and parking benefits, employer-paid health insurance premiums, and most qualified retirement contributions. See payroll deduction for the full pre-tax mechanics.

Federal vs. State Taxable Income Differences

Most states follow federal taxable income, but exceptions exist. Pennsylvania doesn't allow pre-tax 401(k) for state purposes. New Jersey treats some benefits differently than federal. California requires state-specific calculations on certain equity. Check state-specific rules in your payroll system.

Getting Taxable Income Right Across the Pay Cycle

Configure pre-tax deductions correctly in payroll. Audit W-2 Box 1 against expected calculations annually. Train HR on what new benefits add to taxable income (and what they don't). Watch for taxable benefits that get missed (free meals, gym memberships, employer-paid life over $50K). IRS reference: Publication 15.