Methodology · AU-PAY-005
Salary Including Super Calculator
Split a total remuneration package into base salary and employer super, including the maximum contribution base, then estimate tax and take-home pay.
Engines and formulas
- E02 · Australian annual tax engine
Piecewise progressive brackets (§13.13), LITO taper, Medicare levy with low-income phase-in, Medicare levy surcharge tiers and study-loan repayment (marginal from 2025-26, whole-income before), all from versioned rule packs.
Registered formulas: F-TAX-001 progressive brackets · F-TAX-002 LITO · F-TAX-003 Medicare levy · F-TAX-004 MLS · F-TAX-005 STSL
- E03 · PAYG withholding engine
The ATO statement-of-formulas method: y = a·x − b on weekly-equivalent earnings with schedule rounding, plus the Schedule 8 study-loan component. Never annual tax divided by pay periods (§13.16).
Registered formulas: F-PAYG-001 schedule formulas
- E04 · Compensation engine
Package decomposition base = package ÷ (1 + r), capped by the maximum contribution base, with an iterative §12.1.7 verification path.
Registered formulas: F-PAY-001 package decomposition
Rule packs
Statutory values come only from versioned, hash-verified rule packs citing official sources. Current status of the packs this calculator can use:
- au-income-tax-2024-25active · v0.1.0
- au-income-tax-2025-26active · v0.1.0
- au-income-tax-2026-27active · v0.1.0
- au-medicare-2024-25active · v0.1.0
- au-medicare-2025-26active · v0.1.0
- au-medicare-2026-27active · v0.1.0
- au-stsl-2024-25active · v0.1.0
- au-stsl-2025-26active · v0.1.0
- au-stsl-2026-27active · v0.1.0
- au-super-guarantee-2024-25active · v0.1.0
- au-super-guarantee-2025-26active · v0.1.0
- au-super-guarantee-2026-27active · v0.1.0
- au-payg-withholding-2026-27active · v0.1.0
Verification
Engines carry boundary tests at every bracket edge, property-based tests, reconciliation invariants and, where official worked examples exist, tests that reproduce them exactly. The full source register is on the sources page.