You received a bonus, commission or other additional remuneration
This is the most common reason. A bonus, commission, overtime or backpay is additional remuneration, and HASiL assesses it with its own step so a one-off payment does not distort your regular monthly figure. The result is that the pay period carrying the bonus can show a much larger PCB than a normal month, even though your basic salary has not changed.
If this is the cause, the increase is usually confined to the month the extra pay landed, and the next month typically returns closer to your usual PCB.
Your salary increased or payroll made an adjustment
A pay rise, a promotion, a new fixed allowance or the removal of a previous deduction all lift your taxable income. Because PCB is built from your income annualised across the year, a higher monthly base pushes the estimate up — and the change tends to persist rather than reverse next month. Payroll timing matters too: if an increment is applied mid-year with arrears, the catch-up amount is treated much like additional remuneration for that period.
Your year-to-date information is missing or has changed
PCB for later months depends on what has already been deducted year to date. If your accumulated taxable income, EPF, PCB or zakat figures are missing, reset or entered differently — for example after a payroll system change — the calculation can behave as if less tax has been collected so far and try to make up the difference in the current month. Mid-year job changes are a frequent trigger here.
Your family status, zakat or TP1 reliefs changed
Reliefs and rebates reduce PCB, so losing or reducing them raises it. If a spouse relief no longer applies, a child relief was removed, your monthly zakat deduction stopped, or an approved Form TP1 relief was not carried into this month, your chargeable income rises and PCB follows. This can also happen when a relief you submitted was simply not keyed in yet.
You started a new employer without prior-employment (TP3) data
When you change jobs, your new employer needs your prior-employment figures — reported through Form TP3 — to continue your PCB correctly. Without that context, the new employer may start your year-to-date from zero and annualise as if the new salary applied all year, which can make early PCB at the new job look high. Providing accurate TP3 details lets payroll align the calculation with tax already deducted earlier in the year.
Checklist: compare this month with last month
Put this month’s payslip next to the previous one and look for what actually changed:
- Is there a bonus, commission, overtime or backpay line this month?
- Did your basic salary or fixed allowances go up?
- Is your EPF contribution the same as last month?
- Did a zakat deduction stop or change?
- Are your reliefs — spouse, children, approved TP1 items — still applied?
- Did you change employer, and were TP3 prior-employment figures provided?
- Do the year-to-date totals continue smoothly from last month?
Whichever line changed is almost always the reason PCB moved.
What the DuitMap calculator can and cannot tell you
The PCB Calculator can show you an estimated Monthly Tax Deduction for a given set of inputs, so you can test a scenario: run your normal salary, then add the bonus, or change a relief, and see how the estimate moves. That is a fast way to sense-check whether a specific item explains your higher month.
It cannot read your actual payslip or your employer’s records, so it cannot confirm a keying error, benefits-in-kind, a special regime, or the exact year-to-date figures your payroll used. Treat its output as an estimate for understanding, not as the official deducted amount.
When to ask payroll or HASiL
If the checklist points to a clear cause — a bonus, a pay rise, a dropped relief — you usually have your answer. Contact your payroll team when a specific line looks wrong: a relief you submitted is not applied, your year-to-date totals do not continue from last month, or TP3 figures from a previous employer were never entered. For questions about the official calculation method, benefits-in-kind, or how PCB reconciles with your final assessment, HASiL is the authoritative source.