TAX · SPT · Substantial Presence Test

Substantial Presence Test (SPT): 31-Day + 183-Day Formula and Exempt Individuals

The Substantial Presence Test counts US days across three years: all of 2025, one-third of 2024, and one-sixth of 2023. If the weighted total is 183 or more (and you were present at least 31 days in 2025), you are a US tax resident for 2025.

By Marcus Liang · Last verified · Tax year 2025

What the SPT Determines

The Substantial Presence Test determines whether a foreign national is a US tax resident or non-resident alien for a given tax year. Per IRS guidance, residents file Form 1040 on worldwide income; non-residents file 1040-NR on US-source effectively-connected income.

SPT is a counting test — it doesn't depend on visa status directly, though some visa holders are "exempt individuals" whose days don't count.

The Two-Prong Test

To meet SPT, both prongs must be satisfied:

  1. At least 31 days physical presence in the United States in the current year
  2. Weighted three-year total ≥ 183 days: full days in current year + (days in prior year / 3) + (days in second-prior year / 6)

If both prongs are met, the filer is a US tax resident for that year. Otherwise, non-resident alien status applies.

Exempt Individuals

Some individuals' days don't count toward SPT, regardless of physical presence. Per IRS exempt-individual rules:

  • F-1 students: exempt for the first 5 calendar years
  • J-1 / Q-1 students: exempt for the first 5 calendar years
  • J-1 / Q-1 trainees / teachers / researchers: exempt for the first 2 of the past 6 calendar years
  • Foreign government / international organization workers: exempt as long as in qualifying status

Exempt status requires filing Form 8843 even with no income — the form documents the exempt-individual claim.

Worked Example — F-1 Student

Sara is on F-1 from August 2021 through December 2026. Her exempt-individual period: 2021, 2022, 2023, 2024, 2025 (5 calendar years). Days in 2026 are no longer exempt.

For tax year 2026: she has 365 days physical presence (still in F-1). 2025 doesn't count (exempt). 2024 doesn't count (exempt). SPT calculation: 365 (2026) + 0 (2025 exempt) + 0 (2024 exempt) = 365 ≥ 183. Sara becomes a US tax resident in 2026.

Implications of Becoming a Tax Resident

Once SPT is met, the filer transitions from 1040-NR to 1040. Key impacts: worldwide income (not just US-source) becomes taxable, FICA exemption ends (Social Security + Medicare apply on subsequent wages), FBAR filing may be required if foreign accounts exceed $10,000.

Year of transition can be split: dual-status filer files both 1040-NR (for non-resident portion) and 1040 (for resident portion), or makes a §6013(g)/(h) election. See IRS Publication 519 for transition-year rules.

Treaty Tie-Breaker

Bilateral tax treaties may override SPT result. Most US tax treaties include a "tie-breaker" provision determining residency when both countries claim the filer. Tie-breaker tests look at: permanent home availability, center of vital interests, habitual abode, and citizenship.

Treaty tie-breaker can let an SPT-resident filer claim non-resident status for treaty purposes — typically used by short-term assignees who don't intend to remain in the US long-term.

Cross-Pillar Reading

Bottom line

Verdict: Substantial Presence Test is governed by IRS Publication 519 and the Form 1040-NR instructions. Treaty claims and exempt-individual status can shift outcomes meaningfully — verify against the instructions for the relevant tax year.

Frequently asked questions

What is the India treaty Article 21(2)?
Article 21(2) of the US–India Income Tax Treaty lets Indian students and business apprentices in the US claim the standard deduction on Form 1040-NR — $15,750 for single filers in tax year 2025 (2026 filing season). Other NRAs cannot take the standard deduction.
Do I need to file FBAR as a non-resident alien?
FBAR triggers when you are a US person — defined more broadly than just citizens. Becoming a US tax resident (via SPT) makes you a US person for FBAR. Days you held NRA status do not count toward FBAR.
What is the deadline for tax year 2025?
Non-resident filers: April 15, 2026 if you had W-2 wages, June 15, 2026 otherwise. Extensions via Form 4868 are automatic. FBAR (FinCEN 114) is also April 15 with auto-extension to October 15.
Who needs to file Form 1040-NR?
Form 1040-NR is required for non-resident aliens engaged in a US trade or business (including most W-2 wages), and for those with US-source income that needs treaty exemption claims. Students in exempt status still file Form 8843 even with no income.
What is the difference between Form 1040 and 1040-NR?
1040 covers worldwide income for US residents; 1040-NR covers only US-source effectively-connected income (and certain FDAP) for non-residents. Filing status options, deductions, and credits differ substantially.

Sources

This page is not legal advice. Visa-bulletin cut-offs and USCIS processing times can change without notice. Consult a licensed immigration attorney for case-specific guidance.