Form W-4 for a Canadian Working in the US: The Non-Resident Alien Instructions, the Resident-Year Switch, and What Not to Claim

Form W-4 tells a US employer how much federal income tax to withhold from wages. For a Canadian employee, the form is completed one way in a year the employee is a non-resident alien (with instructions that assume single status and deny the standard deduction) and another way once the employee is a US resident (the ordinary form, with filing status and dependents). Treaty exemptions on wages are not claimed on the W-4; they are claimed on Form 8233, which the employer submits to the IRS. And the W-4 does not cover FICA (which follows the totalization agreement and the visa) or state withholding (which has its own forms). The common errors: a non-resident claiming married status or dependents, a new resident leaving the NRA instructions in place, and a treaty-exempt employee expecting the W-4 to stop withholding.

Key takeaways

• Non-resident alien employees complete Form W-4 under Notice 1392: check "single or married filing separately" regardless of actual status; do not claim the child tax credit or other dependents (except for residents of Canada and Mexico in limited cases); write "Nonresident Alien" or "NRA" in the space below Step 4(c); do not claim exemption from withholding. The employer then adds a fixed amount to wages for the withholding computation to offset the standard deduction the NRA cannot claim.
• Resident alien employees (from the residency start date) complete the ordinary Form W-4: actual filing status, dependents, other income and deductions, and extra withholding, like any US employee. Update the form when residency begins.
• Canadian residents' exception: a non-resident alien who is a resident of Canada may claim the child tax credit and credit for other dependents on the W-4 for qualifying dependents who are US citizens or residents (or under the treaty's non-discrimination provisions in limited cases), subject to the 1040-NR rules.
• Treaty exemption: a Canadian whose US wages are exempt under Article XV (under $10,000, or under 183 days with a non-US employer and no US PE) files Form 8233 with the employer, who submits it to the IRS; the W-4 is not the vehicle.
• FICA: not controlled by the W-4; applies to H-1B, TN, L-1, and green card employees from the first paycheque, unless a totalization certificate of coverage exempts a temporary transferee; F-1, J-1, and certain other non-resident visa holders are exempt.
• State withholding: separate state forms (or the federal W-4 by reference); non-resident alien rules vary; no-tax states have none.

The non-resident year

A Canadian who arrives mid-year on a work visa and does not meet the substantial presence test until later (or who commutes and never meets it) is a non-resident alien for withholding purposes until residency begins. Under IRS Notice 1392, the employee completes Form W-4 by: entering personal information; checking the single or married filing separately box (a non-resident cannot file jointly); leaving the dependent credits blank (with the Canadian-resident exception); entering any additional withholding in Step 4(c); and writing "Nonresident Alien" below Step 4(c). The employer computes withholding using the special table that adds a phantom amount to wages, because a non-resident cannot claim the standard deduction and the withholding tables assume it. The employee does not claim exemption from withholding (line for exempt status) even if a treaty applies.

The result is higher withholding than a resident would face on the same wages; any excess is recovered on the 1040-NR (or the dual-status return) after the year.

The resident year

From the residency start date (the first day of presence in the year the substantial presence test is met, or the green card date), the employee is a resident alien and completes an ordinary Form W-4: actual filing status (married filing jointly if the spouse is also a resident or the 6013(g) election will be made), dependents (the child tax credit for qualifying children with SSNs), other income (Canadian-source income if it will be on the 1040), deductions if itemizing, and extra withholding. The "NRA" annotation is removed. Employers do not automatically update the form; the employee must submit a new one.

For a mid-year arrival, the year is dual-status: NRA withholding for the non-resident period, resident withholding after. Many employers apply one or the other for the whole year; the return corrects it.

Treaty exemptions: Form 8233, not W-4

A Canadian employee whose wages are exempt under Article XV does not use the W-4 to stop withholding. The employee completes Form 8233 (identifying the treaty article, the expected exempt amount, and the dates), the employer reviews and submits it to the IRS within five days, and after ten days without objection the employer stops withholding on the exempt wages. The form covers one employer and one year. Wages above the exempt amount, or after the 183-day window closes, are withheld normally. A Canadian employed directly by a US company rarely qualifies (the employer is US-resident, so only the $10,000 rule applies).

FICA

Social Security and Medicare withholding is determined by the visa and the totalization agreement, not the W-4. H-1B, TN, L-1, O-1, E-2, and green card employees are subject to FICA from the first pay. An L-1 transferee (or other temporary transfer of up to five years) from a Canadian employer can stay on CPP with a certificate of coverage from Service Canada, which the US employer keeps on file to exempt the wages from FICA. F-1 and J-1 non-resident aliens are exempt while non-resident. A Canadian commuter who is a non-resident alien working for a US employer is subject to FICA (the totalization agreement assigns employees to the country where they work, with the temporary-transfer exception).

State withholding

States with income tax have their own withholding certificates (New York's IT-2104, California's DE 4) or accept the federal W-4. Non-resident alien rules at the state level vary; some states follow the federal NRA instructions, others do not. A Canadian working in a no-tax state (Texas, Florida, Washington, Nevada, and others) has no state withholding. A Canadian commuter or business traveler working in a state part of the year has state withholding on the days worked there, on a non-resident basis.

The common errors

• A non-resident alien claiming married filing jointly and three dependents: under-withholding, a balance due with the 1040-NR, and possibly a penalty.
• A new resident leaving the NRA form in place for years: over-withholding, refunds each year, and a cash-flow cost.
• A treaty-exempt employee claiming "exempt" on the W-4: the employer withholds anyway (the W-4 exemption is for taxpayers with no tax liability, not treaty claims), or the IRS questions it; Form 8233 was the vehicle.
• A Canadian commuter's employer not withholding FICA on the theory that the employee is Canadian: the agreement assigns commuters to US coverage.

Worked example

A Toronto engineer starts an H-1B job in Seattle on September 1, single, with no US presence earlier in the year.

• September to December. 122 days; the substantial presence test is not met in the arrival year (below 183 with no prior-year days). Non-resident alien for the year. Form W-4 under Notice 1392: single, no dependents, "NRA" below Step 4(c). FICA from the first pay (H-1B, direct hire). No Washington state income tax.
• Following January 1. Residency begins (the prior year's days now count: 122 ÷ 3 = 41, plus the current year's days). New Form W-4: single, standard withholding; the NRA annotation removed.
• Arrival year return. 1040-NR reporting the September-to-December wages; the NRA withholding (higher) produces a refund. No treaty exemption (US employer; wages above $10,000).
• Alternative. If she had arrived June 1, the test would be met in the arrival year (214 days), residency from June 1, and the ordinary W-4 from the start, with a dual-status return for the year.

Official sources

The IRS explains that nonresident alien employees complete Form W-4 with special instructions, including checking single or married filing separately status and writing 'Nonresident Alien' on the form, and that treaty exemptions on wages are claimed on Form 8233. — Internal Revenue Service, Publication 519, U.S. Tax Guide for Aliens, https://www.irs.gov/publications/p519

"This form is used by nonresident alien individuals to claim exemption from withholding on compensation for personal services because of an income tax treaty or the personal exemption amount." — Internal Revenue Service, About Form 8233, https://www.irs.gov/forms-pubs/about-form-8233

"The Agreements help fill gaps in benefit coverage for workers who divide their careers between the United States and an Agreement country." — Social Security Administration, Totalization Agreement with Canada, https://www.ssa.gov/international/Agreement_Pamphlets/canada.html

Practitioner note

The W-4 is where a Canadian's first US paycheque goes wrong in one of two directions: the non-resident who claims a family and is under-withheld, or the new resident who never replaced the NRA form and is over-withheld for years. We fill it in with the client at hire, calendar the residency start date, and file the new one the week residency begins.

See also: Planning a move? Start with the Canada-to-US tax checklist and browse every corridor by city, province, and state.

Next step

Fairlight prepares the W-4 completion for the non-resident and resident periods, the Form 8233 where a treaty exemption applies, and the FICA and state withholding review at hire. See cross-border pricing or book a call.