Savings Account Bonus Condition Simulator
See what a bonus saver actually pays month by month: interest if you meet every condition, if you miss some months, and if you only ever earn the base rate.
Last verified: 12 September 2026Reviewed by the Savings Mate editorial team — figures fact-checked against the ATO, Services Australia and ASIC MoneySmart.
How much do I actually earn if I miss my savings account's bonus conditions?
On $20,000 with $500 deposited each month at 0.35% base plus 4.65% bonus (5.00% p.a.), meeting every condition earns $1,188.25 over 12 months. Miss 2 of those months and you earn $990.52 — $197.73 less — while the base rate alone would pay just $81.50. Estimate only. Source: ASIC MoneySmart.
How this is calculated
Each month, the deposit (and any withdrawal) lands on day 1. Interest for the month is the balance after those movements multiplied by the annual rate divided by 12. In months where the conditions are met, the portion of the balance up to the cap earns base plus bonus; in missed months it earns the base rate only. The portion above the cap earns the base rate (or nothing, if you untick that option). Interest is credited at month end and earns interest itself from the next month.
Missed months are spread evenly across the horizon — 2 of 12 lands on months 6 and 12 — because the exact months you miss are unknown in advance. Missing early months costs slightly less than missing late ones, since the balance is smaller. “Interest lost” is the all-conditions-met total minus your plan's total. The effective annual rate is total interest divided by the average monthly balance, annualised over the horizon.
Assumptions: monthly rather than daily accrual; deposits and withdrawals on day 1; no account fees; rates held constant for the whole horizon; the bonus is lost for a whole month at a time. The condition type you pick is recorded in the notes but does not change the maths — enter your own expected missed months for that condition.
Sources: ASIC MoneySmart — Savings accounts (bonus and honeymoon rates) — checked 12 Sep 2026; ASIC MoneySmart — Compound interest — checked 12 Sep 2026.
What to do next
If the withdrawal rule is what trips you up, read does withdrawing money lose your savings account bonus? for how each condition type treats a withdrawal. Then run your closing balance through the compound interest calculator to see the multi-year picture, or set a target date with the savings goal calculator.
General information and estimates only — not financial, tax, or legal advice. Always verify with a licensed adviser or the ATO.
Related reading
Best rates hit 5.35% in 2026 = $2,675/yr on $50K. We compare Australia's top high-interest savings accounts by rate, conditions, and bonus rules.
Best High Interest Savings Accounts Australia March 2026Top rates hit 5.35% = $2,675/yr on $50K. Best Australian high-interest savings accounts for March 2026, bonus conditions, and ongoing rates.
Best Savings Account Rates March 2026: Where to Park Your Cash at 4.10%With the RBA cash rate at 4.10%, savings account rates are competitive again. We cover the best high-interest savings accounts (up to 5.50%), term deposits, and offset accounts — plus how much $50K, $100K, and $200K earns per year at each rate tier.
RBA Interest Rate Cut March 2026: What It Means for Mortgages and SavingsThe RBA has cut the cash rate again in March 2026. Here's what it means for your mortgage repayments, savings accounts, and what to expect next.