Saving & Investing
Find the return your savings goal would require.
Enter your starting balance, regular contribution, target and timeframe. Calfiny estimates the annual interest rate needed to reach that goal and shows what the journey could look like.
Interest Rate Calculator
Estimate the annual return needed to reach a future savings target.
Your target, timeframe and contributions determine the return that would be needed.
See how much could come from your own money and how much would need to come from growth.
Illustrative route to your target
Year-by-year projection using the estimated required rate.
Try changing the timeframe or regular contribution to see how the required return changes. A lower required rate is generally easier to plan around, but no return is guaranteed.
This calculator estimates the annual rate needed to reach a target. It is illustrative only and does not predict or guarantee the return available from any savings account or investment.
What determines the interest rate you need?
The required rate is mainly shaped by three inputs. Change any one of them and the annual interest rate needed to reach the target can change too.
Starting amount
A larger amount at the beginning means less growth may be needed to reach the target.
Target value
A higher target generally requires a higher rate if the other inputs stay unchanged.
Time available
More time allows interest to build over more periods, which can reduce the annual rate required.
How the required interest rate changes
The calculator solves for one annual rate, but the relationship between your inputs is useful in its own right.
More time
can lower the interest rate required
Larger starting amount
can lower the interest rate required
Higher target
can raise the interest rate required
These relationships assume the other inputs stay unchanged. Changing several assumptions at once can alter the result in different ways.
A calculated rate is not necessarily an available rate
The calculator tells you the rate the maths requires to reach your target. It does not tell you what rate a savings account will offer now or in the future.
The result is a mathematical requirement
It is the annual rate needed to connect your starting amount, target value and timeframe using the assumptions entered.
Actual savings rates can be different
Savings providers set their own rates, and those rates can change over time. A calculated rate may be above or below the rates available in the market.
Rate labels matter when comparing accounts
Measures such as AER help show the effect of compounding when savings rates are compared. The calculator result should not be treated as a product quote.
Use the result as a planning benchmark rather than evidence that a particular savings rate is available.
Explore your next question
Use the calculated rate as a starting point, then choose the question that best matches what you want to understand or calculate next.
Go deeper
These guides explain the interest concepts behind the calculation without turning the calculator result into a product recommendation.
What Is Interest?
Understand what interest means, why rates matter and how interest can affect the value of savings over time.
Read the guide →Common questions about required interest rates
These answers cover the questions that often arise when a financial target is converted into a required annual interest rate.
What does the Interest Rate Calculator calculate?
It estimates the annual interest rate needed for a starting amount to reach a target value over the timeframe you enter, using the calculator’s stated assumptions.
Is the calculated interest rate guaranteed to be available?
No. The result is a mathematical requirement, not a quote or forecast of the rate a bank or savings provider will offer.
Why does more time reduce the interest rate required?
More time gives interest more periods to build. If the starting amount and target stay the same, that can reduce the annual rate needed to reach the target.
Why does a larger starting amount reduce the rate needed?
A larger starting amount leaves a smaller gap for interest to bridge before the target is reached, assuming the target and timeframe do not change.
Does compounding frequency affect the result?
It can. The timing of compounding affects how interest builds, so the calculator should be used with the compounding assumptions shown alongside its inputs and results.
Is an interest rate the same as AER?
Not necessarily. AER is a standardised measure designed to show the effect of compounding over a year, which can make savings accounts easier to compare.
Can savings account interest rates change?
Yes. Variable savings rates can change, while fixed-rate accounts normally hold a stated rate for a defined term subject to the account conditions.
What if the rate I need is higher than current savings rates?
Treat that as a planning signal. You could test a longer timeframe, a different target or a larger starting amount rather than assuming the required rate will become available.