Calculation methodology

What FinanceOS calculates

• Australian resident PAYG salary, employer super, tax, Medicare levy, HELP repayment, take-home pay, essential spending, and modelled surplus or shortfall.
• HELP indexation estimates using the visible rate and financial-year assumption.
• User-created scenario comparisons using the assumptions visible in the app.

What FinanceOS does not calculate

• Tax return lodgement outcomes, tax agent assessments, or ATO account balances.
• Personal financial, investment, credit, legal, tax, or superannuation advice.
• Product suggestions, provider rankings, or instructions about actions to take.

Current assumptions

Tax year

2026-27

HELP repayment

$69,528 minimum repayment income threshold; marginal method

HELP indexation

2.8% on 2027-06-01

Medicare levy

Current-law model: $28,011 low-income threshold; $35,013 phase-in limit for single/no-dependants taxpayers.

2026-27 low-income thresholds are set retrospectively each Budget and have not been announced yet.

Medicare levy low-income thresholds are indexed retrospectively each Budget. The 2026-27 values were not announced at last review, so the model carries the enacted 2025-26 $28,011 threshold and $35,013 phase-in limit for a single taxpayer not entitled to SAPTO.

Super Guarantee

12% from 2025-07-01

Rounding rules

Model calculations keep decimal precision internally, then round visible currency values where the UI needs whole dollars.

Known exclusions

• Australian resident PAYG model only.
• Medicare levy low-income modelling is for a single taxpayer with no dependants. The 2026-27 thresholds are not yet announced, so FinanceOS carries the enacted 2025-26 $28,011 / $35,013 values until they are legislated.
• Repayment income extras such as reportable fringe benefits and reportable super contributions are not included unless explicitly entered elsewhere in the app.
• The model is general information and does not replace ATO, employer, accountant, adviser, super fund, or provider records.

Official sources

• Australian Taxation Office - resident tax ratesLast reviewed 2026-07-02
• Australian Taxation Office - Medicare levy thresholdsLast reviewed 2026-07-12Medicare levy low-income thresholds are indexed retrospectively each Budget. The 2026-27 values were not announced at last review, so the model carries the enacted 2025-26 $28,011 threshold and $35,013 phase-in limit for a single taxpayer not entitled to SAPTO.
• Federal Register of Legislation - Medicare Levy Act 1986Last reviewed 2026-07-12The 2025-26 uplift to a $28,011 threshold amount and $35,013 phase-in limit for taxpayers not entitled to SAPTO is enacted; the ATO published these as current guidance on 30 June 2026. The register's compilation available at review time (C2025C00323) covers periods up to 30 June 2026.
• Australian Taxation Office - study and training loan repayment thresholdsLast reviewed 2026-07-02
• Australian Taxation Office - study and training loan indexation ratesLast reviewed 2026-07-02The 1 June 2027 rate (lower of CPI and WPI) is published by the ATO around April 2027 after the December-quarter ABS prints. Until then the model carries the confirmed 1 June 2026 rate of 2.8% as a planning assumption.
• Australian Taxation Office - study and training loan indexation ratesLast reviewed 2026-05-31
• Australian Taxation Office - Super Guarantee percentageLast reviewed 2026-07-02