Detailed statutory analysis & overview
Potongan Cukai Bulanan, also called Monthly Tax Deduction or MTD, is Malaysia's pay-as-you-earn mechanism, and it is the employer's legal obligation rather than the employee's. Under the Income Tax (Deduction from Remuneration) Rules, an employer must compute PCB on every payment of remuneration and remit it to the Lembaga Hasil Dalam Negeri by the 15th day of the following month, usually through the e-PCB Plus or e-CP39 portals. The calculation is deliberately forward-looking: rather than taxing each month in isolation, the computerised formula annualises your remaining income for the year, applies the progressive scale and your declared reliefs, then spreads the resulting liability across the remaining months, which is why PCB can move sharply mid-year after a raise or a bonus. Crucially, PCB is only an estimate of your final liability, and employees who never tell their employer about reliefs they are entitled to overpay all year and wait for a refund. Two forms fix that: the TP1 lets you declare reliefs during the year so PCB falls immediately, and the TP3 reports income from a previous employer so a mid-year job change does not underdeduct.