Superannuation family law split calculator — pre & post cohabitation
A quick read on the matrimonial superannuation pool.
Enter the dates and balances you have. The tool projects the pre-cohabitation balance forward through an assumed return and isolates the matrimonial component. Educational only — not a court-ready report.
Glossary
Key terms used in this calculator
Plain-English definitions for the inputs and concepts behind a pre & post cohabitation superannuation split.
- Cohabitation date
- The date the relationship became a de facto or married cohabiting relationship — the boundary between pre-cohabitation super (generally non-marital) and post-cohabitation super (generally part of the matrimonial pool). Use the earliest of the move-in date, marriage date, or other clear evidence of cohabitation.
- Pre-cohabitation balance
- The member's superannuation balance on the cohabitation date, taken from the member statement closest to that date. This balance is rolled forward to the valuation date so it can be compared in today's dollars.
- Post-cohabitation / matrimonial component
- The portion of super accrued during the relationship — broadly, the balance at separation minus the pre-cohabitation balance grossed-up to today's dollars. This is the pool typically considered for splitting under s 79 / s 90SM of the Family Law Act.
- Balance Benchmark Rating
- Our cohort-matched estimate used when an opening statement is not available. It blends APRA Heatmap returns for the member's fund and investment option with ATO contribution averages for their age, income and gender cohort to estimate a defensible pre-cohabitation balance.
- Assumed net return
- The annual after-fees, after-tax return used to gross-up the pre-cohabitation balance to the valuation date. The 6.5% default is a long-run proxy for an APRA balanced option — lower it for conservative options, raise it for high-growth options.
- Assumed split of post-cohabitation pool
- The percentage of the matrimonial component allocated to the non-member spouse for illustration. Real splits under s 79(4) / s 90SM(4) are matter-specific, weighing contributions, future needs and other factors — not a fixed 50/50.
- Valuation date
- The date balances are valued at — most commonly the date of separation, but it can be the hearing date or another agreed date. All projections in the calculator are expressed as at this date.
- Sensitivity (±1.5%)
- We flex the assumed return up and down by 1.5 percentage points to show how dependent the estimate is on the return assumption. A formal report uses fund-specific actual returns or a documented benchmark with stated reliance.
Disclaimer. The estimator uses a single deterministic rate of return and simplified assumptions. It does not account for actual fund-specific returns, contributions, rollovers, fees, insurance premiums, defined-benefit factors, SMSF asset valuations, member tax components, or s 79(4) factors such as contributions and future needs. It is provided for general educational purposes. No actuary–client relationship is created by use of this tool. For an expert report suitable for mediation or court, contact us for a fixed-fee engagement.