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Compound interest and your savings account

With compound interest, the interest you earn on your savings is added to your account, and you then earn interest on the interest itself. It's the secret to growing your savings faster.

What is compound interest?

Compound interest means you earn interest on your initial savings balance and any interest you've already accumulated. This is different to simple interest, where your interest is only calculated on the initial balance.

For example, if you earned $20 in interest in a year and you had $800 in your account, then once that interest is paid you'd have $820. Then you'd earn interest on $820 instead of just $20.

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Our expert says

"Compounding is like a magic trick that makes your money grow faster, or your debt grow bigger. Either way, it means that small, consistent efforts – even as little as paying $20 extra into your mortgage, super or savings each week – can make a big impact down the track."

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How does compound interest work?

The best way to explain how compound interest works is with an example.

  • Let's say you invest $1,000 in an account with an interest rate of 5% p.a. compounded for 5 years.
  • The initial investment of $1,000 earns $50 in the first year, giving you a total of $1,050.
  • The following year, you still earn the same rate of 5% p.a. – but this time it's applied to $1,050, not $1,000.
  • This will make your balance $1,102.50 after the second year, even though you haven't deposited any extra money into the account yourself.
  • This amount ($1,102.50) is the base for compounding for the third year, and so on. After 5 years, you'll have $1,283.
  • If your money was in an account earning simple interest, you would earn returns based on the initial $1,000 only (an amount of $50 per year, every year). After 5 years, you'd have $1,250.

The longer your timeline ahead of you, the more your balance grows. In our fictional example, after 10 years, you'd have $1,647. After 20 years, $2,713. And after 50 years, $12,119 – without ever adding an extra cent of your own money.

To get the most benefit out of compound interest, deposit as much as you can into your account and restrict the number of withdrawals you make. The more money that is in your account at the end of the month, the more interest you will earn.

How can compound interest help you grow your savings?

compound interestCompound interest can turn a small amount of money today into a large amount of money over the space of 10, 20 or 30 years.

The longer your timeline ahead of you, the more you stand to benefit from compound interest. For example, if you are 22 years old and set some savings aside for retirement at age 65, you have 43 years of compound growth in your future.

How do banks calculate compound interest?

Interest is typically calculated on a daily basis on the daily closing balance. Here's the savings account equation:

  • Daily closing balance x interest rate (as a percentage) / 365

Interest begins to accumulate on the day the opening deposit is made in your savings account. It's then usually credited into your account on the last day of each month. If you choose to close your account, your accrued interest will be deposited on the day it's closed.

Any interest awarded to your savings account is usually available for use on the same day it's been credited. The daily closing balance of your savings account tends to include all cleared and uncleared transactions. This may be because electronic transfers to your linked bank account usually occur on a business day.

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Our expert says

"I would almost always put money into a savings account over a term deposit. Savings accounts earn compound interest (meaning you earn interest on the interest paid), whereas most term deposits only earn simple interest (meaning you earn interest only on the initial deposit)."

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How do you find the monthly interest rate?

The monthly variable interest rate will be clearly displayed on the provider's website under the product description for the particular account you’re looking at. Instead of going to each bank's website, you can take a look at the latest high interest savings account interest rates in our guide. It is important to remember that the interest rate is variable, meaning it will change from time to time.

What are the pros and cons of compound interest?

Pros

  • Easy access to your money. The majority of Australian savings accounts that provide compound interest allow you to make withdrawals and additional deposits whenever you need to.
  • Lower balance requirements. Many accounts that offer compound interest do so with a low minimum balance requirement.
  • Bonus rates. You can find savings accounts with compound interest that do give you an incentive of bonus interest for not making any withdrawals in a month.
  • Increased interest income. With compound interest, your earnings are being increased exponentially, as each month the interest is being calculated on a slightly higher balance.

Cons

  • Lower rates. The annual rates are usually not as high as accounts like term deposits, where your money is locked into an account for a set period.
  • Accessibility. For some Australians, having open access to your savings isn't ideal, as you can easily dip into it for daily needs, causing you to lose a portion of your interest earnings.
  • Timeline. To really get the benefits of compounding, you want to be in it for the long haul. You may get better returns on your money in other ways if you have a shorter timeline to work with.
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Compare compound interest accounts

One of the main ways to earn compound interest is with a savings account. These accounts usually calculate your interest daily and pay interest monthly, so the following month you can earn interest on the interest you've just earned. This is why they're such a popular option for growing your money.

1 - 15 of 188
Name Finder Score Maximum Variable Rate p.a. Standard Variable Rate p.a. Intro/Ongoing Government Guarantee Monthly Max Rate Conditions
Ubank High Interest Save Account
Ubank logo
Finder score
9.6
Maximum Variable Rate p.a.
5.50%
Standard Variable Rate p.a.
0.00%
Intro/Ongoing
Ongoing
Government Guarantee
Monthly Max Rate Conditions
  • Deposit $500
  • Savings up to $100,000
Go to siteView details
Rabobank High Interest Savings Account
Rabobank logo
Finder score
8.3
Maximum Variable Rate p.a.
5.75%
Standard Variable Rate p.a.
4.40%
Intro/Ongoing
4 months
Government Guarantee
Monthly Max Rate Conditions
  • Balances up to $250,000
Go to siteView details
ING Savings Accelerator ($150,000 - $500,000)
ING logo
Finder score
8.6
Maximum Variable Rate p.a.
5.40%
Standard Variable Rate p.a.
4.70%
Intro/Ongoing
4 months
Government Guarantee
Monthly Max Rate Conditions
  • Welcome rate applies up to $500K
Go to siteView details
Newcastle Permanent Smart Saver Account - Under 25s
Newcastle Permanent logo
Finder score
8.8
Maximum Variable Rate p.a.
5.00%
Standard Variable Rate p.a.
0.05%
Intro/Ongoing
Ongoing
Government Guarantee
Monthly Max Rate Conditions
  • Grow balance
  • No more than 2 withdrawals
Go to siteView details
Macquarie Savings Account
Macquarie Bank logo
Finder score
8.7
Maximum Variable Rate p.a.
5.35%
Standard Variable Rate p.a.
4.75%
Intro/Ongoing
4 months
Government Guarantee
Monthly Max Rate Conditions
  • Balances up to $250,000
Go to siteView details
Bank of Queensland Simple Saver Account
BOQ logo
Finder score
8.8
Maximum Variable Rate p.a.
4.85%
Standard Variable Rate p.a.
4.85%
Intro/Ongoing
Ongoing
Government Guarantee
Monthly Max Rate Conditions
  • Balances up to $5,000,000
Go to siteView details
Suncorp Bank Growth Saver Account
Suncorp Bank logo
Finder score
9
Maximum Variable Rate p.a.
5.05%
Standard Variable Rate p.a.
0.35%
Intro/Ongoing
Ongoing
Government Guarantee
Monthly Max Rate Conditions
  • Grow balance by $200 each month (excl. interest)
  • Only 1 withdrawal
  • No balance limit on earning interest
Go to siteView details
ING Savings Maximiser
ING logo
Finder Award
Finder score
9.6
Maximum Variable Rate p.a.
5.50%
Standard Variable Rate p.a.
0.55%
Intro/Ongoing
Ongoing
Government Guarantee
Monthly Max Rate Conditions
  • Deposit $1,000
  • 5 transactions
  • Grow your balance
  • Balances up to $100,000
Go to siteView details
ME HomeME Savings Account
ME logo
Finder score
9.7
Maximum Variable Rate p.a.
5.55%
Standard Variable Rate p.a.
0.55%
Intro/Ongoing
Ongoing
Government Guarantee
Monthly Max Rate Conditions
  • Deposit $2000
  • Grow balance
  • Balances up to $100,000
Go to siteView details
Newcastle Permanent Smart Saver Account
Newcastle Permanent logo
Finder score
7.9
Maximum Variable Rate p.a.
4.50%
Standard Variable Rate p.a.
0.05%
Intro/Ongoing
Ongoing
Government Guarantee
Monthly Max Rate Conditions
  • Grow balance
  • No more than 2 withdrawals
Go to siteView details
First Option Bank Savings+Bonus Account
First Option Bank logo
Finder score
8.7
Maximum Variable Rate p.a.
5.00%
Standard Variable Rate p.a.
2.00%
Intro/Ongoing
Ongoing
Government Guarantee
Monthly Max Rate Conditions
  • Deposit $100
  • No withdrawals
  • Balances up to $249,999
Go to siteView details
IMB Reward Saver Account
IMB logo
Finder score
6.1
Maximum Variable Rate p.a.
5.25%
Standard Variable Rate p.a.
0.00%
Intro/Ongoing
4 months
Government Guarantee
Monthly Max Rate Conditions
  • Deposit $50
  • No withdrawals
  • Balances up to $1,000,000
Go to siteView details
Earn up to 3.25% p.a. after the introductory period ends.
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How the Finder Score helps you find a better savings account

The Finder Score is a simple score out of 10. The higher a savings account's score, the better we think it is for the average customer.

We score each savings account in our database of hundreds based on a data-driven methodology with 2 main criteria: Does the account offer a high interest rate? And is it easy for savers to actually earn that rate?

Read the full Finder Score breakdown

Frequently asked questions

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To make sure you get accurate and helpful information, this guide has been edited by Moira Daniels and reviewed by Karen Eley, a member of Finder's Editorial Review Board.
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Written by

Editor

Alison Banney is the money editorial manager at Finder. She covers all areas of personal finance, and her areas of expertise are superannuation, banking and saving. She has written about finance for 10 years, having previously worked at Westpac and written for several other major banks and super funds. See full bio

Alison's expertise
Alison has written 645 Finder guides across topics including:
  • Superannuation
  • Savings accounts, bank accounts and term deposits
  • Budgeting and money-saving hacks
  • Managing the cost of living

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