Skip to content

Offset Account Calculator

AustraliaScheduled modelClass B · rule-based estimateNo statutory rules requiredMethodology
AUD
Enter the annual rate as a percentage, like 5.99.

Repay interest only for the first years, then principal and interest.

Cash sitting in the offset account. It stays yours and is never treated as a repayment.

AUD
AUD

Cash taken back out. Interest rises from that date, because the balance stops being offset.

AUD
Defaults to the first repayment, 1 Oct 2026.

Enter your loan and an offset balance or regular deposit to see the interest and time saved.

Summary

Two ledgers run on identical dates: one with the offset balance and deposits, one with neither. Offset cash reduces the interest-bearing balance under §13.9 while staying yours to withdraw.

Working

  1. §13.5 payment — the scheduled repayment solves P = B·i ÷ (1 − (1 + i)^−n) from the balance B, the periodic rate i and the remaining periods n.
  2. §13.7 recurrence — each period: interest = accruing balance × i, then closing = opening + interest + fees − payment − extra repayment.
  3. §13.9 offset — interest accrues on max(0, balance − offset × effectiveness), floored at zero; offset cash is never a principal repayment.
  4. §12.5.8 reconciliation — the ledger identity is checked on every period. A reconciliation failure invalidates the result rather than warning about it.
  5. §12.6 offset vs principal — a deposit to offset lowers the accruing balance but not the debt; an extra repayment lowers the debt and cannot be withdrawn unless redraw allows it.

Assumptions

  • Interest accrues once per repayment period on the payment-period ledger. Daily accrual is not modelled at P0.
  • The first repayment falls on 1 October 2026; every date in the schedule follows from that and the repayment frequency.
  • The rate is held constant except where a dated rate-change event moves it.
  • Weekly, fortnightly and monthly frequencies use 52, 26 and 12 periods per year.

Limitations

  • Lender daily accrual, transaction timing, fee timing and rounding can differ from this model; compare the settings with your loan contract and statements.
  • Redraw availability, offset eligibility conditions, break costs and any lender fee that was not entered are not modelled.
  • Amounts beyond the entered term are not projected; a balance left unpaid at term is reported rather than extended.