Refix / refinance calculator
See whether breaking your current fixed mortgage early to refix at a lower rate is likely to pay off.
What this means for you
See the break-even break fee — the amount your bank would need to quote before switching stops being worth it.
Compare time remaining
The months left on your current fix is one of the biggest levers in this decision — see how the verdict shifts.
| Scenario | Verdict | Net amount |
|---|---|---|
| 6 months less | — | $0 |
| Current | — | $0 |
| 6 months more | — | $0 |
More months remaining means more time for the interest saving to outweigh the break fee — that's why switching tends to make more sense earlier in a fixed term than near the end of it.
Assumptions & sources
Break fee is a rough estimate based on the retail rate gap — banks calculate real break fees from wholesale swap rate movements, which aren't publicly available. Always confirm the real figure with your bank.
1 July 2026
17 July 2026
Net benefit = (monthly interest saving × months remaining) − break fee. Monthly interest saving is the gap between your current and new rate applied to your remaining balance.
Interest cost difference over your remaining fixed months, minus the break fee.
Admin or legal fees some refinances involve, and any effect of refixing for a different total term than your original loan.
How break fees actually work
A break fee isn't simply the gap between your old and new retail rates — it's the bank's estimate of what it costs them to unwind the wholesale funding arrangement they made when you fixed. That's driven by wholesale swap rates, which move differently to the retail rates banks advertise to customers, so a rough estimate based on retail rates (like the default in this calculator) can be meaningfully off in either direction. Always get an exact quote from your bank before committing.
Even with an exact break fee, the decision usually comes down to how much time is left on your current fix and how big the rate gap is. A large rate drop with a year or more remaining often clears the break fee comfortably; a small rate drop with only a few months left rarely does.
Frequently asked questions
What a bank charges to end a fixed-rate mortgage early, based on their economic cost of unwinding the wholesale funding for your loan — driven by wholesale rate movements, not the retail rate gap, which is why only your bank can quote it precisely.
Generally when the interest saved by refixing lower exceeds the break fee plus any admin costs. This is most likely when rates have fallen significantly and you have meaningful time left on your term — a few months left rarely saves enough to be worth it.
