Methodology
Singapore Resident Income Tax — YA 2026 methodology
Educational only: Work and pay decision support, not tax, legal, financial or career advice.
Privacy: Calculations run locally; Wage101 does not receive your work or pay inputs.
Update policy: Reviewed when formulas or official dependencies change.
Scope: Singapore work and pay planning using your own assumptions.
1. Formulas and units
netTaxOnChargeableIncome = round to cents(grossTaxOnChargeableIncome − rebateUsed)Where
- netTaxOnChargeableIncome
- Tax on entered chargeable income (SGD/YA)Source: Calculated output
grossTaxOnChargeableIncome = round to cents(sum of each YA 2026 resident band slice × its statutory rate)Where
- grossTaxOnChargeableIncome
- Gross tax before rebate (SGD/YA)Source: Calculated output
rebateUsed = min(taxRebate, grossTaxOnChargeableIncome)Where
- taxRebate
- Confirmed tax rebate (SGD/YA)Source: User assumption
- rebateUsed
- Rebate used (SGD/YA)Source: Calculated output
marginalRate = statutory YA 2026 resident rate for the highest chargeableIncome band reachedWhere
- chargeableIncome
- User-entered chargeable income (SGD/YA)Source: User assumption
- marginalRate
- Marginal resident rate (share)Source: Calculated output
effectiveRate = chargeableIncome is zero ? 0 : netTaxOnChargeableIncome ÷ chargeableIncomeWhere
- chargeableIncome
- User-entered chargeable income (SGD/YA)Source: User assumption
- effectiveRate
- Effective rate on chargeable income (share)Source: Calculated output
Money inputs and outputs use SGD. Pay, time, benefits and work-related costs use the units stated beside each input.
2. Worked example
Input assumptions
Apply YA 2026 resident rates to S$80,000 of entered chargeable income.
Calculation and outputs
Example
Apply YA 2026 resident rates to S$80,000 of entered chargeable income.
- Tax on entered chargeable income
- 3,350.00 currency units
- Gross tax before rebate
- 3,350.00 currency units
- Rebate used
- 0.00 currency units
- Marginal resident rate
- 7%
- Effective rate on chargeable income
- 4.2%
Gross tax, rebate and net tax remain separate.
Interpretation
Use the result as a resident chargeable-income estimate, not complete tax advice.
3. Validation and boundary checks
- The worked example uses the same shared-work-logic engine as the interactive planner.
- Unsupported eligibility, policy branches and out-of-range assumptions fail closed.
- Result cards, trace, CSV, PDF and methodology bind to named engine result fields.
4. Assumptions and source classification
- The user has already established tax residence and chargeable income.
- Any entered rebate has been independently confirmed.
Official dependencies used by this calculator are captured in the Wage101 evidence register and version-acknowledged in this page history. User-entered work and pay assumptions remain separate from those official inputs.
5. Limitations
- This does not derive chargeable income from salary, reliefs or deductions.
- It is not a salary tax, payroll withholding or take-home-pay calculator.
This is educational decision support, not personalised tax, legal, financial or career advice. Check how the rules that apply in Singapore treat your work and pay circumstances, and seek qualified advice where appropriate.
6. Update and evidence policy
Registered family-level suites test formula invariants and example reconciliation; the release ledger records that coverage without claiming a separate oracle for every line of public copy. Registered official sources block dependent public workflows when their evidence or version acknowledgement is unavailable or invalid. Work and pay inputs remain user-supplied because they vary by person, job and contract.
Change history
- : Initial public release of the Singapore Annual Income Tax planner and methodology.
Related reading
Use these practical guides to interpret the decision and its assumptions.
- Singapore resident income tax for YA 2026: scope and calculation
Estimate Singapore resident income tax from annual chargeable income using reviewed YA 2026 rates.
Read guide