Methodology · AU-BIZ-006
Contractor Day Rate Calculator
Convert a target income into a contractor day rate covering super replacement, leave, overheads and utilisation, with GST quoted separately.
Engines and formulas
- E19 · Contractor economics engine
Billable capacity from weekdays minus leave, holidays and non-billable days times utilisation; day rate covers income, super replacement, overheads and the chosen margin. GST is quoted on top and never treated as revenue.
Registered formulas: §12.16 capacity
- E20 · Business arithmetic engine
GST arithmetic per §13.18 with explicit rounding levels and largest-remainder allocation so invoice lines always reconcile to totals.
Registered formulas: F-GST-001 · F-GST-002
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-gst-standardactive · 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.