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Sri Lanka Advanced Tax Calculator

For years that don't fit in a payslip: consulting income from local and foreign clients, work-from-home deductions, equipment allowances, a property sale, rent and FDs — combined the way the IRD combines them, with your deadlines laid out.

In short

Model complex Sri Lankan tax situations for 2025/26: multiple income sources, freelancer deductions, the 15% remitted-FX cap, rent cost options, and AIT credits — with a full band-by-band breakdown of the result.

What happened in your year?

Tap everything that applies — then we’ll go through them one short step at a time.

Step 1

Estimates for a resident individual, Y/A 2025/26 rules (Inland Revenue Act No. 24 of 2017 as amended in 2025). Work-use percentages are reasonable splits, not official formulas; equipment is depreciated straight-line over 5 years. This is guidance, not tax advice — confirm with a Chartered Accountant or tax practitioner before paying or filing.

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Who this advanced calculator is for

The simple income tax calculator answers most people’s question in a minute. This one is for the messier years: you consulted for a Colombo company and a foreign client, bought a laptop for work, pay home rent where you also work — and maybe sold a block of land in July. Each of those has different rules, and two of them have different deadlines.

What you can deduct — and what you can’t

Deductions apply only against self-employment and consulting income — the law allows expenses “incurred in the production of income”. A salary gets no expense deductions at all, and neither does FD interest. Within consulting income:

Cost	Deductible?	How
Transport, fuel for work	Yes	The work-use share
Phone, internet, software/SaaS	Yes	The work-use share (subscriptions used only for work: 100%)
Electricity, utilities, home rent (working from home)	Partly	A reasonable share of the space/usage — no official formula exists; the private part is never deductible
Laptops, monitors, equipment	Yes — over 5 years	Capital allowance: 20% of the price per year, not all at once
Entertainment, private spending, fines	No	Expressly disallowed
Cash payments of Rs. 500,000+	No	Disallowed unless paid through the banking system

Inland Revenue Act No. 24 of 2017: s.11 (deduction), s.10 (disallowed items, incl. domestic expenses and large cash payments), Fourth Schedule (capital allowances).

One more thing worth knowing: deductions reduce your foreign-currency income too — the 15% ceiling applies to profit, not turnover, so every documented cost saves you tax on both sides.

Sold land, a house, or unlisted shares? Read this first

Capital gains are the odd one out: taxed separately at 10%, with their own return and payment due within 30 days after the end of the month of the sale — not with your November return. Tiny gains escape entirely: a gain under Rs. 50,000 is exempt (as long as your gains for the year stay under Rs. 600,000). If you owned the asset from before April 2018, your “cost” is its market value as at 30 September 2017, which usually shrinks the taxable gain substantially — a valuer’s report is worth the fee. Selling the home you’ve owned for three years and lived in for two of them, or shares listed on the Colombo Stock Exchange, is generally outside the net — confirm your case before paying.

Why the calculator talks about quarterly payments

Consulting, rent and interest income have no employer withholding tax monthly, so if tax is still owing after your credits, you pay it yourself in four instalments — 15 August, 15 November, 15 February and 15 May — against a Statement of Estimated Tax, settling by 30 September and filing by 30 November. The calculator works out whether that applies to your mix and splits the amount for you.

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Check before you act

Work-use percentages are honest estimates, not official formulas; capital-gains exemptions turn on your specific facts; and deductions only survive an IRD query with receipts behind them. These are suggestions — confirm everything with a Chartered Accountant or tax practitioner before paying or filing.

Evidence for the rules used

Deductions and disallowed items: Inland Revenue Act (consolidated), ss.10–11; capital allowances: Fourth Schedule
Rates, relief, 15% FX ceiling, interest AIT: IRD Notice PN/IT/2025-01
Capital gains: separate 10% taxation of investment-asset gains, 30-day return (IRA s.93(3)) and the 30.09.2017 deemed-cost rule for pre-2018 assets
Instalments and deadlines: IRD Tax Calendar (IRA ss.90, 93)

Complex years

What complex earners ask most.

Can I deduct my internet, phone and transport as a freelancer? +

Yes — against your consulting or self-employment income, to the extent they're used for work. Sri Lanka has no official percentage formula for mixed personal-and-work costs, so the practice is an honest, defensible split (say 50% of your internet if half your use is work), backed by bills you keep. Purely private spending is never deductible, and none of this applies against a salary — employees get no expense deductions.

Can I claim my laptop against tax? +

Yes, but not all at once. Computers and equipment used for your business are capital assets, deducted as capital allowances over five years — 20% of the price each year. A Rs. 600,000 laptop gives you a Rs. 120,000 deduction annually for five years, starting from the year you began using it for work. Keep the invoice.

How much tax do I pay when I sell land in Sri Lanka? +

10% of the gain — the sale price minus what the asset cost you. If you owned it since before April 2018, the cost is its market value as at 30 September 2017, which usually reduces the gain a lot. The tax is separate from your annual income tax: its return and payment are due within 30 days after the end of the month of the sale. Selling your own principal residence is generally exempt, subject to conditions.

My income changes every month — how do I estimate quarterly payments? +

Use your best estimate of the full year, pay a quarter of the estimated tax at each date (15 August, 15 November, 15 February, 15 May), and revise the estimate as the year firms up — the law explicitly allows updating your Statement of Estimated Tax. Whatever remains after the year ends is settled by 30 September, and the return by 30 November reconciles everything.

Deductions only count if the return is filed right.

LankanTax turns your invoices, receipts, allowances and credits into a ready-to-lodge return — free for individuals, reviewed and lodged by a Chartered Accountant who can defend every deduction you claim.

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Free for individuals. Your CA’s professional fee is the only cost — shown upfront.