A tax year is any period of 12 consecutive months commencing on 1 April of one calendar year and ending on 31 March of the following calendar year.
An individual is required to file a return of income in a prescribed format (with financial statements and supporting schedules, if applicable) not later than eight months after the end of each year of assessment (on or before 30 November immediately following the end of the tax year).
Spouses are taxed separately on their individual incomes.
Payment of tax
Under the pay-as-you-earn (PAYE) tax system, employers are required to deduct from the monthly emoluments of each employee income tax computed on the basis of statutory tables provided by the tax authority. In general, where employment is an individual's only source of income, the tax deducted by the employer and paid to the tax authority is the final income tax due from the employee. Individuals with income from other sources other than final withholding payments on which tax has been deducted are entitled to set off the annual income tax deducted by the employer from the overall income tax payable.
Under Sri Lanka's pay-and-file system, individuals other than employees are required to pay tax in instalments on or before 15 August, 15 November, 15 February of the tax year, and 15 May immediately following its end.
The amount of each instalment of tax payable by an instalment payer for a year of assessment shall be calculated based on an estimate of tax payable for the current year, and it should be filed with the Commissioner General by the date for payment of the first tax instalment.