Compound Interest Calculator

See how savings grow with interest and regular contributions.

Final balance

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In today's dollars–

Total deposited–

Interest earned–

Year by year

Year	Deposited	Interest	Balance

Estimate only, before tax and fees, at a rate that never changes. This calculator is not intended to be relied on for the purposes of making a decision about a financial product. You should consider obtaining advice from a financial services licensee (a licensed financial adviser) before making any financial decisions. Purpose, assumptions and limitations are below the chart.

Balance by year

Purpose, assumptions and limitations

What it's for: seeing how a starting amount and regular deposits could grow with compound interest at a rate you choose, so you can compare rates, amounts and time frames. It's general arithmetic: it doesn't recommend or compare any bank account, term deposit or investment.

Today's dollars: The final balance is in future dollars: the money in your account at the end, with no allowance for prices rising in the meantime. The in today's dollars figure divides it by 1 plus the inflation rate for each year until then (the present value), so you can see what it would buy at today's prices. It uses 2.5% a year unless you change it: the middle of the Reserve Bank's 2–3% inflation target, and the default set by ASIC Corporations (Generic Calculators) Instrument 2026/41 (section 6), which asks calculators like this one to show it for amounts 2 or more years away.

Default assumptions and why they're reasonable:

$10,000 to start, $200 a month and 10 years: an example, so the page shows a result straight away. Enter your own figures.
5% a year: an example rate in the range Australian high-interest savings accounts and term deposits have paid in recent years. It isn't a quote; enter the rate your account actually pays.
Interest added monthly and deposits made monthly: how most Australian savings accounts work. Deposits are spread evenly through each compounding period.
The same rate for the whole time, with no tax and no fees: this keeps the result to the effect of compounding alone. The limitations below say what that leaves out.

Limitations and their effect: tax isn't taken off: interest is taxable income, so at a 30% marginal rate plus the 2% Medicare levy you'd keep about two-thirds of the interest shown. Rates change, and many bonus rates need conditions met each month, so your real balance will differ. Fees aren't included. For investments such as shares, returns vary from year to year and can be negative, so a steady rate makes the result look more certain than it is.

Not for product decisions: This calculator is not intended to be relied on for the purposes of making a decision about a financial product. You should consider obtaining advice from a financial services licensee (a licensed financial adviser) before making any financial decisions.

How compound interest works

Checked 15 Oct 2026. Uses the same approach as Moneysmart's compound interest calculator, so you can cross-check a result there.

Compound interest means you earn interest on your interest. A lump sum grows by the formula A = P(1 + r/n)^nt, where P is the starting amount, r the yearly rate as a decimal, n the number of times interest is added each year and t the years. Regular deposits are added each period and earn interest from then on.

Worked example: $10,000 at 5% a year, compounded monthly, for 10 years: $10,000 × (1 + 0.05/12)¹²⁰ = $16,470. Add $200 a month and you finish with $47,527: $34,000 you put in and $13,527 of interest.

How often interest is added

On that $10,000 over 10 years at 5%, yearly compounding gives $16,289, monthly $16,470 and daily $16,487. Time and rate matter far more than frequency: $200 a month at 5% grows to $82,207 in 20 years but $166,452 in 30, when interest ($94,452) has overtaken your deposits ($72,000).

Saving in Australia

Interest from a bank account or term deposit is taxable income, taxed at your marginal rate, and this calculator shows it before tax. Deposits with Australian banks, building societies and credit unions are protected by the government's Financial Claims Scheme up to $250,000 per person per institution, as Moneysmart explains. Many high-interest savings accounts pay their bonus rate only if you deposit or don't withdraw each month, so check the conditions. Inflation also eats into growth, so each result also shows the final balance in today's dollars, at 2.5% inflation a year unless you change it (the middle of the Reserve Bank's 2–3% target, and ASIC's default for calculators). The inflation calculator shows what money was worth in past years.

General information only, not financial, tax or credit advice. Check your situation with the ATO, your state revenue office or a licensed adviser.

Compound interest FAQs

How much will $10,000 grow to in 10 years at 5%?

$16,470 with interest compounded monthly, or $16,289 compounded yearly. That's $6,470 of interest, before tax, with nothing added.

How much will I have if I save $200 a month?

$82,207 after 20 years at 5% compounded monthly, of which $48,000 is your deposits. After 30 years it's $166,452, and interest ($94,452) is more than you put in.

Does compounding frequency matter much?

A little. $10,000 at 5% for 10 years grows to $16,289 compounded yearly, $16,470 monthly and $16,487 daily. Time and rate matter far more.

Does this include tax?

No. Interest earned in a savings account is taxable income in Australia, taxed at your marginal rate. Results also ignore fees and rate changes.

What is the result worth in today's dollars?

Less than it looks, because prices rise in the meantime. The $47,527 you'd have after 10 years from $10,000 plus $200 a month at 5% is worth about $37,128 in today's dollars, at 2.5% inflation a year. After 30 years, the $166,452 from $200 a month is worth about $79,355 in today's dollars. The calculator shows this under every result, and you can change the inflation rate.

Can I use this for investments?

Yes, as a rough guide with an expected average return, but investment returns vary year to year and aren't guaranteed.