Both an offset account and a redraw facility work the same way: they reduce the loan balance you're charged interest on, so your money effectively "earns" your mortgage rate, and unlike savings-account interest, it isn't taxed. Dollar for dollar, they save the same interest. The difference is everything around that.
How each one works
An offset account is a normal transaction or savings account linked to your loan. Its balance is subtracted from the loan before interest is calculated, and you can spend from it any time like a regular account. A redraw facility lets you pull back the extra repayments you've made ahead of schedule. The money is inside the loan until you ask for it.
Dollar for dollar, they save the same interest. The difference is everything around that.
Where they differ
The interest saved is identical. What changes is access, tax exposure if things change later, discipline and cost:
Offset vs a savings account
An offset usually beats parking cash in savings, because savings interest is taxed and offset interest saved isn't:
At a 30% marginal rate, a 5% savings return is really about 3.5% after tax. The ATO takes its share of the interest every year.
An offset returns your full mortgage rate, and none of it is taxable income because it's interest you never paid, not interest you earned.
For anyone with a home loan, that's hard for cash savings to beat.
The bottom line
If you might ever turn the home into an investment, or you want your savings fully liquid and clearly yours, offset is usually the cleaner choice. If you just want somewhere to stash extra repayments and value the tiny bit of friction, redraw is fine. Either way, keeping cash against the loan almost always beats a taxed savings account.
Enter your loan, rate and offset balance for the interest saved and years knocked off.
General information only, not financial advice.