Sri Lanka Tax Residency Calculator — 183-Day Rule

Sri Lankan tax residency for individuals is decided by section 69 of the Inland Revenue Act No. 24 of 2017 (still the operating text after the amendments of 2022, 2023, and 2025). The section gives three independent tests — satisfying any one of them makes you resident for the whole year of assessment.

1. Domicile / habitual abode(section 69(1)(a)) — you reside in Sri Lanka. The calculator captures this through the "habitual abode" toggle; flipping it on is a self-declaration that your primary year-round home is here.
2. 183-day presence (section 69(1)(b)) — you are physically present in Sri Lanka for 183 days or more in any 12-month period that commences or ends during the year of assessment. The 12-month window does not have to line up with the 1 April – 31 March tax year, which is why a stay straddling two YOAs can still trigger residency.
3. Government posting (section 69(1)(c)) — you are an employee or official of the Government of Sri Lanka posted abroad during the year. The day count is irrelevant; the deeming rule covers you for the whole year regardless of physical presence.

The mechanical work is in the 183-day test. The calculator runs two parallel checks and reports both:

• YOA-only count — for each travel period, intersect with the YOA window and countmax(0, min(departure, YOA_end) − max(arrival, YOA_start) + 1)days. Both endpoints are inclusive, so a trip from 15 Sep through 20 Sep is 6 days, not 5. Sum across rows.
• Rolling 12-month scan — build a deduplicated set of every day you were present in Sri Lanka (across all trips). For each candidate 365-day window whose start or end falls inside the YOA, count how many of those days are in the window. Report the window with the most days; if any window touches 183, the 183-day test is satisfied even when the YOA-only count falls short.

The output panel shows the verdict, the controlling test, the YOA day count, and (when the rolling toggle is on) the best 365-day window. A parallel cross-check function —crossCheckYoaPresenceByPeriodSum— recomputes the YOA count via a naive per-row intersection sum and the calculator flags any difference. The two methods agree to the day when trips do not overlap; when they do overlap, the deduplicated count is the legally correct one because the Act counts days of presence, not day-trips.

Resident versus non-resident — what actually changes

Residents are taxed on worldwide income at the same progressive 6%–36% ladder used by the Sri Lanka Income Tax Calculator, with personal relief of Rs 1,800,000 a year for Y/A 2025/26 and a foreign-tax credit under section 89 for tax already paid overseas. Non-residents face the same rate ladder but the relief is zero and the only income inside the net is Sri Lanka-source — typically local salary, local consulting fees, dividends from resident companies, rent on Sri Lanka property, and so on. Withholding tax at 15% applies to most service fees and rent paid to a non-resident; non-resident citizens on regular payroll face APIT at the 14% non-resident rate.

Edge cases the calculator deliberately handles

(1) Exact 183-day boundary— a stay from 30 Sep 2025 through 31 Mar 2026 counts as exactly 183 days; the verdict is Resident because the threshold is "183 days or more". A single day shorter (1 Oct 2025 start) yields 182 days and a Non-Resident verdict. (2) Overlapping trips — if two rows cover the same physical day, that day is counted once in the YOA total and the cross-check banner flags the difference. (3) Rolling-window catch — a foreign citizen present 1 Oct 2024 through 15 Apr 2025 has only 15 days inside Y/A 2025/26 but the 365-day window starting 1 Oct 2024 contains the full 197-day stay; that window ends inside the YOA, so section 69(1)(b) is satisfied. (4) Reversed dates — if the departure is earlier than the arrival, the row is rejected with a clear error rather than counted as a negative day count. (5) Trips two years outside the YOA — silently dropped because they cannot affect either the YOA count or any 365-day window touching the YOA.

Three scenarios that map to the most common Sri Lankan situations, worked end to end against section 69. Try each one in the calculator above — the day count should match to the day.

• IRD — Inland Revenue Act No. 24 of 2017 and subsequent amendments (section 69 — Resident persons)
• IRD — Tax Chart for Resident and Non-Resident Individuals (Y/A 2025/26)
• IRD — Public Ruling PR/IT/2020/02 on source of employment income
• Inland Revenue Department of Sri Lanka — official site

Section 69 was last cross-checked against the IRD-published consolidation of the Inland Revenue Act No. 24 of 2017 (as amended by Acts Nos. 45 of 2022, 04 of 2023, and 02 of 2025) on 2026-05-17. This page is reviewed every April when a new year of assessment begins.