Substantial Presence Test Calculator
Apply the IRS current-year, one-third and one-sixth weights while separating exclusions and exceptions. Sensitive inputs stay in your browser.
The IRS test requires at least 31 countable days in the current year and 183 weighted days across three years.
Context matters.
- Meeting the arithmetic test does not resolve exempt-individual days, treaty tie-breakers, closer-connection exceptions or filing obligations. Use IRS Publication 519 and professional advice.
Sources & scope
The calculation guide and this source trail show what the result means, where the rule came from and when it was last reviewed. This is source-and-calculation QA, not a claim of medical, legal, tax or other professional review; time-sensitive decisions still belong with the linked authority.
A visible path from input to answer.
Apply the IRS current-year, one-third and one-sixth weights while separating exclusions and exceptions. The page keeps the calculation scope and its limits beside the result so the output can be checked, copied or revisited.
- Read the record. The calculator uses Countable U.S. days this year, Countable U.S. days last year, Countable U.S. days two years ago and Current-year days confirmed as excluded supplied in the form.
- Apply the scope. It applies the United States federal tax-residency arithmetic — IRS exclusions, exceptions, treaties and filing rules control reference and the explicit date, unit and counting conventions shown in the result.
- Expose the checkpoints. Intermediate rows, warnings and timeline events stay visible; the emphasized row identifies the primary checkpoint when one exists.
The IRS test requires at least 31 countable days in the current year and 183 weighted days across three years.
- Weighted total180
Calculation purpose: Apply the IRS current-year, one-third and one-sixth weights while separating exclusions and exceptions. This is a high-sensitivity reference output; the linked authority or qualified professional controls the final decision.
Numeric inputs are constrained by the field limits and the result keeps the entered units visible. Zero, minimum, maximum and non-finite values are treated as input boundaries.
Rule set 1.1.0 · Last reviewed 2026-08-22 · Next review due 2027-02-22. The source panel below contains the linked evidence.
What to know before using the result.
Is the IRS substantial presence test simply 183 days in one year?
No. The standard test also requires at least 31 current-year days and uses all current-year days plus one-third of prior-year days and one-sixth of second-prior-year days.
Are all U.S. presence days counted?
No. The IRS lists excluded-day categories and exceptions. Enter counts only after applying the current official instructions to your facts.
Does meeting the arithmetic test always make someone a U.S. tax resident?
No. Exempt-individual rules, closer-connection relief and treaties can change the conclusion; qualified tax advice may be needed.