Rate change · mortgage impact calculator
The rate moved.
What does it cost you?
Every central bank decision ends in the same question at the kitchen table. Put in your loan, slide the rate, and see the answer in your own numbers — per month, per fortnight, and over the whole life of the loan.
Your loan today
Current repayment $3,221.51 / month
If the rate moves…
Your repayment goes up $76.84 a month — an extra $23,052 in interest over the life of the loan.
- New rate
- 6.25%
- New repayment / month
- $3,298.35
- Change / month
- +$76.84
- Lifetime interest ±
- +$23,052
Every likely move, side by side
Central banks usually move in 0.25% steps. Screenshot this table or copy the link — your numbers travel with it.
| Rate change | New rate | Repayment / month | Change / month | Lifetime interest ± |
|---|---|---|---|---|
| Today | 6.00% | $3,221.51 | — | $466,452 total |
| −0.50% | 5.50% | $3,070.44 | −$151.07 | −$45,321 |
| −0.25% | 5.75% | $3,145.53 | −$75.97 | −$22,792 |
| +0.25% | 6.25% | $3,298.35 | +$76.84 | +$23,052 |
| +0.50% | 6.50% | $3,376.04 | +$154.53 | +$46,359 |
| +1.00% | 7.00% | $3,533.90 | +$312.39 | +$93,717 |
Good to know
What is the cash rate, and why does it move my mortgage?
The cash rate (RBA in Australia; the federal funds rate in the US; Bank Rate in the UK) is the benchmark interest rate set by the central bank. Lenders fund their loans at prices anchored to it, so when it moves, variable mortgage rates usually follow — typically by the same 0.25% or 0.50% step.
How quickly do banks pass a change on?
For variable-rate loans, most lenders announce their response within days of a central bank decision, with the new rate taking effect two to four weeks later. Cuts are sometimes passed on more slowly, or only partially — this calculator assumes the full change flows through, which is the common case for rises.
I'm on a fixed rate. Does this affect me?
Not while the fixed period lasts — your repayment is locked. It matters at the end of the term: your loan reverts to a variable rate, and every move between now and then shifts the rate you'll land on. Try entering your revert scenario above to preview the change before it arrives.
Why fortnightly repayments?
Many lenders (especially in Australia and New Zealand) let you pay fortnightly. This calculator uses a true fortnightly schedule — 26 payments a year with interest charged per fortnight — not a monthly figure split in half.
How is the repayment calculated?
With the standard amortization formula: payment = P × r ÷ (1 − (1 + r)⁻ⁿ), where P is your balance, r the rate per period and n the periods remaining. It assumes the rate stays at the new level for the remaining term, and ignores fees, offset accounts and extra repayments. Everything runs in your browser — nothing is uploaded or stored.
This tool provides general information only and is not financial advice. Your lender’s actual repayments may differ depending on fees, rounding, offset balances and how the change is passed on. Talk to your lender or a licensed adviser before making decisions.