Sri Lanka Partnership Income Tax Calculator — 2025/26

A Sri Lankan partnership is taxed differently from an individual. Under the Inland Revenue Act No. 24 of 2017 (as amended), the firm itself bears a flat partnership charge, and the profit is then apportioned to the partners. This calculator applies the partnership regime for Year of Assessment 2025/26 (1 April 2025 – 31 March 2026):

1. Set the taxable base. Add the divisible profit (the trading profit shared among partners) to any other partnership income such as interest: base = divisible profit + other income.
2. Apply the Rs 1,000,000 threshold. The first Rs 1,000,000 of that base is tax-free. Only the excess is charged: tax on income = max(0, base − 1,000,000) × 6%.
3. Charge realisation gains separately. Gains from realising investment assets are taxed at 10% with no threshold — the same rate our capital gains tool cites, kept as one shared constant so the two never drift.
4. Total and split.Add the two charges for the firm's total tax. The divisible profit is then apportioned to each partner by their profit-sharing weight: share = divisible profit × weight ÷ Σ weights. Weights are auto-normalised, so 60/40, 6/4 and 3/2 all mean the same split.
5. Schedule the installments. The total is paid in four equal quarterly self-assessment installments across the year.

The 6% charge is verified two independent ways in the underlying module: directly as max(0, base − threshold) × 6% and by the equivalent statute form 6% × base − 6% × min(base, threshold), which reconcile to the rupee. A partner's apportioned share is reported on their personal return, but the same profit is not taxed twice — the firm has already borne the partnership charge. Any non-partnership income a partner earns is taxed under the separate personal APIT brackets.

• Inland Revenue Department of Sri Lanka — Guide to Income Tax & partnership return
• Inland Revenue Act No. 24 of 2017 (Incorporating Amendments) — partnership charge & installment dates

The 6% partnership rate, the Rs 1,000,000 threshold and the 10% rate on realisation gains were last cross-checked against the IRD sources on 2026-07-09. This page is reviewed every April (start of the new SL year of assessment) and whenever a new Inland Revenue Amendment Act becomes law.