Sri Lanka: tax on gross, not on what is left
Sri Lankan APIT is charged on the first 1,800,000 rupees free and then across bands rising from 6% to 36%. The detail that catches people out is that the tax is worked out on gross remuneration: your 8% EPF contribution does not reduce the income the bands are applied to. Payroll systems differ on this point, so the calculator says which assumption it is using rather than leaving it implicit.
The employer side is larger than the employee side and never appears as a deduction. Your employer adds 12% to your EPF and a further 3% to the ETF, and the Act bars deducting either from your pay, so both show only in the employer-cost figure.
Worked example: Rs 3,600,000 a year, EPF at the statutory 8%
Personal relief Rs 1,800,000, leaving Rs 1,800,000 taxed across the 6%, 18% and 24% bands, which is as far as this salary reaches: Rs 222,000.
EPF at 8% of the full Rs 3,600,000: Rs 288,000.
Take-home: Rs 3,090,000 a year, Rs 257,500 a month. Total cost to your employer is Rs 4,140,000 once their EPF and ETF contributions are counted.