Working backwards beats hoping forwards
"Save what's left at the end of the month" reliably saves nothing — the month always wins. Reversing the question (goal ÷ time, adjusted for interest) turns a vague hope into a standing transfer you set up once. The maths above solves for the monthly deposit whose future value, plus the growth on what you've already saved, lands exactly on your goal.
Make the transfer invisible
Schedule the transfer for payday — not the day after, payday — into an account at a different bank with no card attached. The behavioural evidence is boringly consistent: money you don't see, you don't spend. Most Australian banks let you name accounts; "House 2029" outperforms "Savings Account 2" for the same reason written goals outperform intentions.
Where to park goal money
| Timeframe | Sensible home | Why |
|---|---|---|
| Under 2 years | High-interest savings / term deposit | No time to recover from a market dip |
| 2–5 years | HISA, or offset if you have a mortgage | Offset "earns" your mortgage rate, tax-free |
| 5+ years | Consider index investments | Growth assets need time to be safe-ish |
| House deposit (first home) | First Home Super Saver Scheme | Save inside super at 15% tax; withdraw up to $50,000 |
Interest helps less than you'd hope (short-term)
Over a 3-year goal at 4.75%, interest contributes maybe 6–8% of the final amount — the deposits do the lifting. That's liberating in one sense: for short-term goals, the rate barely matters, so don't burn hours rate-chasing. Put the energy into the transfer amount instead. (Over 20+ years the opposite is true — see the compound interest calculator.)