Overview

When an employee performs work outside their employer’s state, one or more states may claim the right to tax that income. States use residency tests, sourcing rules (where services are performed), and special doctrines like the “convenience of the employer” test to decide who taxes the pay. Employers must also decide where to withhold state income tax — and that choice is governed by state law, not federal law. For background on how reciprocity can change this outcome, see FinHelp’s primer on How State Reciprocal Agreements Affect Multistate Employees.

Key rules that determine tax treatment

  • Residency: Your resident state typically taxes all income from worldwide sources. States classify residents differently (statutory resident days, domicile tests). See FinHelp’s State Residency Tests Explained for step-by-step tests.

  • Source (where you perform the work): Many states tax income earned from work performed within their borders, even for nonresidents. If you physically work in State A, that state may treat those wages as sourced there.

  • Convenience-of-the-employer: A few states (notably New York) apply a convenience test that taxes remote work as sourced to the employer’s state unless the employee must be remote for employer business reasons. See New York guidance: https://www.tax.ny.gov/.

  • Reciprocal agreements: Some neighboring states have reciprocity and allow withholding and taxation only in the employee’s resident state — these agreements change withholding and filing obligations.

Employer withholding and payroll responsibilities

Employers generally must withhold state income tax where the employee performs services (or per the state law that governs withholding). Payroll teams should:

  1. Track the employee’s work locations.
  2. Register to withhold taxes in states where employees perform taxable work.
  3. Adjust W-4 state equivalents, follow reciprocity forms where available, and consult state withholding guides (see IRS Employer’s Tax Guide, Publication 15: https://www.irs.gov/publications/p15).

Common outcomes and how double taxation is prevented

  • Dual filing: Nonresidents often file a nonresident return in the work state and a resident return at home. To avoid being taxed twice, most resident states allow a credit for taxes paid to other states (check the resident state’s rules).

  • No state tax resident: If your home state has no income tax (e.g., Florida, Texas), you may still owe tax to the state where you performed services.

Real-world example (typical scenario)

If Jane lives in Florida (no state income tax) but performs occasional work for an employer based in New Jersey, New Jersey’s tax treatment will depend on its sourcing rules and whether the duties are considered performed in New Jersey. If she spends time working physically in New Jersey, she’ll generally owe NJ nonresident tax on NJ-sourced wages; if all work is performed in Florida, NJ’s position may differ. For New York employers, remote employees must also consider New York’s convenience rule.

Practical checklist — actions for employees and employers

  • Track location daily: Use timecards or a location log showing where work was performed.
  • Notify payroll: Tell HR and payroll when your work location changes so withholding can be updated.
  • Review state withholding guides: Employers should consult state tax agency guidance and register for withholding as required.
  • File correctly: If required, file nonresident state returns and claim resident credits to offset taxes paid to other states.
  • Get professional help: Multistate filings and credits can be complex—consider a tax pro for Nexus or residency disputes.

Common mistakes to avoid

  • Assuming only your resident state can tax you.
  • Ignoring employer withholding obligations — employers can face penalties for failing to withhold correctly.
  • Not checking reciprocity or convenience rules, which can change where tax is owed.

Brief FAQ

Q: Can I be taxed in both states?
A: Yes. You may owe a nonresident tax where work was performed and resident tax at home. Most resident states allow a credit to reduce double taxation.

Q: What is the “convenience of the employer” rule and where does it apply?
A: It’s a doctrine used by some states (notably New York) that treats income as sourced to the employer’s state when remote work is for the employee’s convenience rather than employer necessity. Check state guidance before assuming remote days are exempt. New York Tax Department guidance clarifies that test for NY.

Sources and further reading

Professional disclaimer

This content is educational and does not constitute tax advice. State rules differ and change; consult a qualified tax advisor or your state tax agency to determine your particular filing and withholding obligations.