How the Effective Annual Rate Calculator Works (With a Worked Example)
Converts a nominal interest rate into an effective annual rate. This guide walks through what each input means, the formula behind the answer and a worked example using typical Australian figures. You can follow along in the free Effective Annual Rate Calculator.
Why it matters
Australians save and invest through bank accounts, term deposits, shares, ETFs and property. Interest and dividends are taxable, franking credits can offset tax on dividends, and inflation steadily reduces the value of money that isn’t growing.
What you need to enter
The calculator asks for 2 inputs. The table shows each one with the example value used later in this guide.
| Input | Example value |
|---|---|
| Nominal annual rate (%) | 5 |
| Compounding periods per year | 12 |
The formula
Effective rate = (1 + nominal ÷ periods)^periods − 1.
Worked example
Entering the example values above gives these results:
| Result | Value |
|---|---|
| Effective annual rate | 5.116% |
The headline figure is 5.116% (effective annual rate). Change any input in the calculator and every result updates instantly, so you can test different scenarios side by side.
How the effective annual rate changes with nominal annual rate
The table below keeps every other input at the example value and moves only “Nominal annual rate (%)” up and down by 10% and 20%. It shows how sensitive the effective annual rate is to that one figure.
| Nominal annual rate (%) | Effective annual rate |
|---|---|
| 4 | 4.074% |
| 5 | 5.116% |
| 6 | 6.168% |
At 4 the result is 4.074%; at 6 it is 6.168%. If a small change in this input moves the answer a lot, it is worth double-checking that figure before you rely on the result.
A practical tip
Use the effective rate to compare accounts that compound monthly with ones that pay interest yearly.
Keep going
Before relying on the number, read Getting the Most From a Effective Annual Rate Calculator: Tips and Common Errors. You might also find these guides useful:
- Bonus Saver Account Calculator: Formula, Example and What the Result Means
- Using a Net Worth Calculator in Australia: A Step-by-Step Guide
- Using a Compound Interest Calculator in Australia: A Step-by-Step Guide
Frequently asked questions
- Are investment returns guaranteed?
- Only some products, such as term deposits, have fixed rates. Share and fund returns vary and can be negative.
- Is my bank deposit protected?
- The Financial Claims Scheme guarantees deposits up to $250,000 per account holder per authorised bank.
- Is this investment advice?
- No. The calculators provide general information only.
Run your own numbers in the Effective Annual Rate Calculator.
Open the calculatorGeneral information only. Rates and thresholds change, usually on 1 July. Confirm current figures with the ATO or the relevant authority, and get personal advice for decisions about your situation.