Multiple Jobs: Tax Guide (2025)

Tips for coordinating withholding, completing Form W-4, and avoiding underpayment penalties.

Withholding Coordination

Designate one job to withhold at the higher single rate or adjust multiple W-4 allowances to reflect combined income.

Estimated Taxes

If you have significant self-employment or side income, make quarterly estimated payments to avoid penalties.

Practical Steps

  • Use the IRS withholding estimator
  • Submit a new W-4 when pay or job mix changes
  • Keep separate records for each income source
  • Consider safe-harbor payments for estimated taxes