Compound Interest Calculator Australia 2025-26
See how your money grows when you give it time.
Watch your money grow. See the power of compounding with contributions, tax, inflation, and fees.
Estimates using standard compound interest formula. Actual investment returns vary.
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Select the question that matches where you are right now.
Compound interest is interest calculated on both the initial principal and all accumulated interest from previous periods. Over long periods, even small amounts grow dramatically — a $10,000 investment at 7% doubles in approximately 10 years and quadruples in 20.
Compare scenarios by adjusting inputs. Use the precision bar to reveal more detail. Results update in real time as you type.
Not professional financial advice, not a guarantee of any specific outcome, and not a substitute for qualified advice for significant decisions.
All calculations run entirely in your browser using standard formulas. No data is sent to any server.
The inputs that most influence this result are shown in the breakdown above. Even small changes to key variables can have a significant compound effect over time.
Longer periods amplify both growth and cost. Starting one year earlier or later can change a financial outcome by more than you expect.
Even a 1% change in rate can materially change the outcome over a long period. Use Standard or Advanced mode to model rate sensitivity.
Most financial variables have a non-linear relationship with the result — they compound. The sensitivity table in Advanced mode shows this clearly.
To improve this result, focus on the inputs with the highest leverage. Small changes to the right variable often produce much larger outcomes than large changes to less important ones.
Adjust inputs one at a time. The one that moves the result most is your binding constraint — focus effort there first.
Use the Scenario A/B feature in Advanced mode to compare two situations side by side.
Many financial decisions benefit from timing. Starting earlier, fixing a rate at the right moment, or clearing a debt before applying for new credit can each produce significant improvements.
Depending on what you are planning, these are the natural next steps after reviewing this result.
This calculator shows one part of a financial decision. The related calculators below help you model adjacent factors.
Switch to Standard or Advanced mode and use the scenario comparison tool to model best, expected, and worst case.
For decisions involving significant amounts of money, use this result as a starting point for a conversation with a qualified financial advisor.
How compound interest is calculated
The compound interest formula
A = P(1 + r/n)^(nt), where A is the final amount, P is the principal, r is the annual rate, n is the number of compounding periods per year, and t is the time in years. Daily compounding (n=365) produces slightly more than monthly (n=12) or annual (n=1).
| Principal | Rate | Period | Annual | Monthly | Daily |
|---|---|---|---|---|---|
| $10,000 | 6% | 10yr | $17,908 | $18,193 | $18,221 |
| $10,000 | 7% | 20yr | $38,697 | $40,102 | $40,208 |
| $50,000 | 5% | 15yr | $103,946 | $104,882 | $104,906 |
Compound interest examples — savings and investments
These figures assume no additional contributions and a fixed rate — actual investment returns vary and are not guaranteed.
| Initial amount | Rate | 5 years | 10 years | 20 years | 30 years |
|---|---|---|---|---|---|
| $5,000 | 5% | $6,381 | $8,144 | $13,266 | $21,609 |
| $10,000 | 6% | $13,382 | $17,908 | $32,071 | $57,435 |
| $20,000 | 7% | $28,051 | $39,343 | $77,394 | $152,245 |
| $50,000 | 8% | $73,466 | $107,946 | $233,048 | $503,133 |
How compounding frequency affects growth
Does daily vs monthly matter?
Yes, but less than most people think. On $10,000 at 6% over 10 years: annual compounding produces $17,908; monthly produces $18,194; daily produces $18,220. The difference between monthly and daily is only $26 over 10 years. The rate itself matters far more than compounding frequency.
When frequency matters most
Compounding frequency matters most at high rates and long time periods. A credit card charging 20% daily vs monthly is a meaningful difference on large balances over years. For standard savings and investment accounts, the difference between monthly and daily compounding is minor.
The Rule of 72 — a quick mental calculation for doubling time
How the Rule of 72 works
Divide 72 by the annual interest rate to get the approximate number of years for your money to double. At 6%: 72 ÷ 6 = 12 years. At 9%: 72 ÷ 9 = 8 years. At 4%: 72 ÷ 4 = 18 years.
| Rate | Doubling time (Rule of 72) | Actual doubling time |
|---|---|---|
| 4% | 18 years | 17.7 years |
| 6% | 12 years | 11.9 years |
| 8% | 9 years | 9.0 years |
| 10% | 7.2 years | 7.3 years |
| 12% | 6 years | 6.1 years |
How regular contributions amplify compound growth
Adding $500/month to $10,000 at 6%
Starting with $10,000 and adding $500/month at 6% produces approximately $83,000 after 10 years and $244,000 after 20 years. Compare this to the $10,000 alone: $17,908 after 10 years and $32,071 after 20 years. Regular contributions are dramatically more powerful than the initial lump sum.
| Monthly contribution | 10yr balance | 20yr balance |
|---|---|---|
| $0 (lump sum only) | $17,908 | $32,071 |
| $200/mo | $51,000 | $115,000 |
| $500/mo | $83,000 | $244,000 |
| $1,000/mo | $147,000 | $465,000 |
Real vs nominal returns — the inflation adjustment
Why inflation matters
If your savings earn 5% per year but inflation is 3%, your real return is only approximately 2%. The exact calculation is: real rate = (1 + nominal) / (1 + inflation) − 1 = (1.05 / 1.03) − 1 = 1.94%. Over 20 years, $10,000 at 5% nominal becomes $26,533 — but that $26,533 only has the purchasing power of approximately $16,545 in today's dollars at 3% inflation.
| Nominal rate | Inflation | Real rate | $10k after 20yr (nominal) | Real purchasing power |
|---|---|---|---|---|
| 5% | 3% | 1.94% | $26,533 | $16,545 |
| 7% | 3% | 3.88% | $38,697 | $24,117 |
| 9% | 3% | 5.83% | $56,044 | $34,930 |
Australian compound interest projections by rate
$200/month at various returns
| Years | 4% return | 6% return | 8% return | 10% return |
|---|---|---|---|---|
| 10 years | $29,400 | $32,800 | $36,800 | $41,300 |
| 20 years | $73,300 | $92,400 | $117,800 | $152,400 |
| 30 years | $138,900 | $201,900 | $300,000 | $456,000 |
| 40 years | $236,800 | $398,000 | $700,000 | $1,265,000 |
$500/month across time horizons (7% return)
| Years | Total contributed | Final value | Interest earned |
|---|---|---|---|
| 10 | $60,000 | $87,000 | $27,000 |
| 20 | $120,000 | $263,000 | $143,000 |
| 30 | $180,000 | $614,000 | $434,000 |
| 40 | $240,000 | $1,335,000 | $1,095,000 |
Starting early: Saver A vs Saver B
Saver A: $200/month from 25-35 (10 years, $24k contributed), stops but leaves invested until 65. At 7%: final balance $146,000.
Saver B: $200/month from 35-65 (30 years, $72k contributed). At 7%: final balance $244,000.
Saver A contributed 3x less but gets 60% of Saver B's balance. Time beats contribution amount.
Where to compound money tax-effectively in Australia
Superannuation — the 15% wrapper
Concessional contributions taxed 15% inside super (vs up to 47% marginal rate). Investment earnings taxed 15% (or 0% in pension phase). Most powerful compounding vehicle for retirement. Concessional cap $30,000/year 2025-26.
ETFs in personal name
Capital gains: 50% discount if held 12+ months. Franking credits from Australian dividends offset tax. Low fees (0.04-0.30% typical). Best for accessible, flexible long-term investing outside super.
High interest savings accounts
Currently 4-5% p.a. Interest taxable at marginal rate. Best for emergency funds and short-term goals (1-2 years). Look for bonus rates with conditions you can meet.
Term deposits
4-5% p.a. locked for 6-24 months. Guaranteed rate. Penalty for early withdrawal. Good for medium-term goals where timing is certain.
Investment property
Long-term capital growth 5-7% + rental yield 3-5%. Leverage amplifies returns. Tax benefits: negative gearing, depreciation. Illiquid and time-intensive. Only for substantial investors.
Listed investment companies (LICs)
Australian-listed investment trusts (AFI, ARG, MLT, WHF). Low fees, fully franked dividends, active management. Some trade at discount to NTA (buying opportunity).
Managed funds vs ETFs
ETFs typically cheaper (0.04-0.30%) than managed funds (0.8-2%). Over 30 years at 7% return on $100k: 0.20% fee = $662k final; 1% fee = $574k. Fee drag of 0.8% costs $88k.
How fees reduce compound returns in Australia
Fee impact on $100,000 over 30 years (7% gross return)
| Annual fee | Net return | Final balance | Lost to fees |
|---|---|---|---|
| 0.10% (cheap ETF) | 6.90% | $740,265 | — |
| 0.30% (typical ETF) | 6.70% | $700,950 | -$39,315 |
| 0.80% (mid-fee fund) | 6.20% | $613,660 | -$126,605 |
| 1.50% (active fund) | 5.50% | $503,310 | -$236,955 |
| 2.00% (high-fee) | 5.00% | $444,030 | -$296,235 |
Super fund fees
Industry funds typically 0.5-1% total. Retail funds 0.8-2%. Large fund (AustralianSuper, Aware, HESTA) generally beat retail on net returns. APRA heatmap ranks fund performance vs fees.
Choice vs MySuper defaults
MySuper is the default option — typically balanced risk profile. Choice products allow sector selection. For most people, MySuper is appropriate. Too much tinkering often hurts returns.
Compound interest for Australian retirement planning
ASFA retirement standards (June 2024)
| Lifestyle | Single annual | Couple annual | Super balance at 67 |
|---|---|---|---|
| Comfortable | $51,815 | $73,031 | $595,000 / $690,000 |
| Modest | $33,085 | $47,731 | Mostly on Age Pension |
How much to contribute to reach comfortable retirement
Starting at 25 with $50k salary, 11.5% SG only (no extras): ~$500k by 65 at 6% return — close to ASFA comfortable but tight. Adding $200/month salary sacrifice: ~$800k. Adding $500/month: $1.1m+ — very comfortable retirement.
The power of starting at 25 vs 35
$1,000/month salary sacrifice from 25: $2.3m at 65 (7% return). Same from 35: $1.2m. Starting 10 years earlier nearly doubles retirement savings — same monthly contribution.
The 4% withdrawal rule
Withdraw 4% of pot in year 1, inflation-adjust thereafter. Historical safe rate for 30+ year retirement. $1m pot supports $40,000/year. Combined with Age Pension (means tested), provides comfortable retirement for moderate pots.
Australian compound interest strategies by life stage
20s — maximum time in market
Every dollar invested at 25 is worth 4x more at 65 than $1 invested at 45 (at 7% return). Priority: build emergency fund, salary sacrifice to super at marginal rate benefit, start ETF investing in taxable or super.
30s — balance competing priorities
House deposit vs investments vs super vs early career growth. Consider: First Home Super Saver (FHSS) to save for home in super. Salary sacrifice more as income grows. Diversify beyond super into low-cost ETFs.
40s — acceleration phase
Earnings usually peak. Maximize concessional super contributions to 30k cap. Catch-up carry-forward if balance under $500k. Review super fund — high-fee funds cost hundreds of thousands over decades.
50s — optimization
Transition to retirement strategies. Boost super via carry-forward. Non-concessional contributions ($120k + bring-forward $360k). Review investment allocation — typically shift slightly to defensive assets as horizon shortens.
60s — preservation and drawdown
Convert super to pension phase (0% earnings tax). Manage sequence-of-returns risk. Consider annuity for certainty on basic expenses. 4% withdrawal rule as starting guide. Keep growth assets for inflation protection.
The 1% difference over 40 years
$10,000 at 7% for 40 years: $149,745. At 8%: $217,245. At 9%: $314,094. Each extra 1% return adds 45-70% to final balance over 40 years. Minimize fees ruthlessly — biggest controllable lever for return.
Best Australian ETFs for long-term compounding
Core Australian ETF options
| ETF | Exposure | Fee (MER) |
|---|---|---|
| VAS (Vanguard Australian Shares) | ASX 300 | 0.07% |
| A200 (BetaShares AU 200) | ASX 200 | 0.04% |
| VGS (Vanguard Intl Shares) | Developed markets | 0.18% |
| VGE (Vanguard Emerging Markets) | Emerging markets | 0.48% |
| DHHF (BetaShares Diversified High Growth) | All-world 100% equity | 0.19% |
| VDHG (Vanguard Diversified High Growth) | All-world 90/10 | 0.27% |
Classic two-ETF portfolio
50% VAS (Australia) + 50% VGS (International developed): weighted average ~0.12% fee. Simple, cheap, diversified globally. Annual rebalance. Outperforms most active funds over 20+ years.
Three-ETF portfolio
Add emerging markets (VGE) for ~10-20% of international allocation. Total three ETFs covers 99% of world's investable equity markets at under 0.15% average fee.
One-ETF solution: DHHF or VDHG
All-in-one diversified ETFs hold global stocks + (sometimes) bonds automatically. DHHF: 100% equity, no rebalancing needed. VDHG: 90% equity, 10% bonds for slight stability. Dollar-cost average monthly, forget about it.
Super vs ETF tax comparison
Super: 15% earnings tax. Taxable ETF: full marginal rate. On 7% return: super keeps 5.95%; taxable ETF at 30% marginal keeps 4.9%; at 47% marginal keeps 3.7%. Super wins dramatically for long-term compounding.
Real vs nominal returns: adjusting for Australian inflation
Real return formula
Real return ≈ Nominal return - Inflation. More precisely: ((1 + nominal)/(1 + inflation)) - 1. 7% nominal - 3% CPI = 4% real return. Real returns determine actual purchasing power growth.
Long-term Australian asset class real returns
| Asset class | Nominal (pre-tax) | Real (after inflation) |
|---|---|---|
| Australian shares | ~9-10% | ~6-7% |
| International shares | ~8-9% | ~5-6% |
| Australian property | ~7-8% | ~4-5% |
| Australian bonds | ~5-6% | ~2-3% |
| Cash / savings | ~4-5% | ~1-2% |
Why real returns matter for retirement
$1 million retirement pot today won't have same buying power in 30 years. At 3% inflation: needs to be $2.4 million to match today's lifestyle. Plan in real terms — retirement calculators should show real dollars.
Asset classes beating Australian inflation
Historically: shares, property, inflation-linked bonds. Cash often struggles after tax and inflation — effective real return can be negative for higher-rate taxpayers.
Inflation hedge allocations
Shares are best long-term inflation hedge (corporate earnings rise with prices). Inflation-linked bonds (ILBs) and TIPS provide direct protection. Property provides partial hedge. Cash rarely keeps pace.
Superannuation vs external investing: which compounds better?
Tax on earnings comparison
| Vehicle | Contribution tax | Earnings tax | Withdrawal tax |
|---|---|---|---|
| Super accumulation | 15% concessional | 15% | 0% after 60 |
| Super pension phase | — | 0% | 0% |
| ETF in personal name | Marginal rate | Marginal rate | CGT (50% discount over 12mo) |
| Investment bond | Post-tax | 30% within bond | Tax-free after 10 years |
$50k/year compounding comparison (30 years, 7% return)
Super (15% earnings tax): ~$4.73m final balance. Same amount invested externally at 32.5% marginal: ~$3.88m. 18% more in super over 30 years — power of 15% vs 32.5% tax drag.
When external beats super
Need access before 60 (super locked). Already hit concessional cap. Short-term goals (under 10 years). Non-working spouse (lower marginal rate than super's 15%).
Pension phase advantage
Transfer super to retirement pension from age 60: 0% tax on earnings up to Transfer Balance Cap ($1.9m in 2024-25). Massive step-up vs pre-retirement super earnings.
Common compound interest mistakes Australians make
Delaying starting because of small amounts
$50/month at 25 beats $200/month starting at 35. Starting later requires dramatically more contribution to reach the same retirement number. The time to start is now, not 'when I can afford more'.
Not maximising employer super match
Many industries offer employer super match above SG (e.g. dollar-for-dollar up to 3%). Not salary sacrificing to capture is leaving free money. Compound over career: $200k+ in missed retirement capital.
Ignoring fees
1% higher fee over 30 years on $10k: loses $60k final balance. Many Australian super funds charge 1.5%+ when 0.3% index option exists. Check PDS, use APRA heatmap.
Timing the market
Missing 10 best market days over 20 years halves return. Trying to predict highs/lows costs more than staying invested. Dollar-cost averaging through regular contributions eliminates timing risk.
Panic selling during drops
March 2020 crash: down 35%. Recovered within year. Sellers crystallised losses. Stayers continued compounding. Match allocation to real risk tolerance — not asset class return.
Keeping too much in cash long-term
Cash 4-5% minus tax minus inflation = often negative real return. Emergency fund needed, but excess cash beyond 6 months erodes purchasing power. Move long-term savings to growth assets.
Simple interest vs compound interest Australia
Formula difference
Simple interest: A = P × (1 + rt). Interest only on original principal. Compound: A = P(1 + r/n)^(nt). Interest on interest. Over time, compound dramatically outperforms simple.
Where you see simple interest in Australia
Some personal loans calculate interest on original balance (flat rate). Some car finance (HP). Term deposits paid out (not compounded). Most other investments compound.
20-year comparison ($10,000 at 7%)
| Method | Final balance | Interest |
|---|---|---|
| Simple interest | $24,000 | $14,000 |
| Annual compound | $38,697 | $28,697 |
| Monthly compound | $40,102 | $30,102 |
| Daily compound | $40,208 | $30,208 |
❓ Frequently asked Frequently asked questions
What is compound interest?
Compound interest is interest calculated on both the initial principal and all previously accumulated interest. Unlike simple interest (calculated only on principal), compound interest causes exponential growth. A $10,000 deposit at 6% compound interest becomes $17,908 after 10 years versus $16,000 with simple interest.
How often does compounding make a significant difference?
Compounding frequency matters most at high rates over long periods. The difference between annual and daily compounding on $10,000 at 6% over 10 years is approximately $312. This difference grows significantly at higher rates — at 12%, the same comparison produces a $1,200 difference over 10 years.
What is the Rule of 72?
The Rule of 72 is a shortcut for estimating how long it takes to double your money: divide 72 by the annual interest rate. At 6%, money doubles in approximately 12 years (72÷6). At 9%, it doubles in 8 years. The rule is accurate within 1–2% for rates between 4% and 15%.
Does inflation erode compound growth?
Yes. Your real return is your nominal interest rate minus inflation. If you earn 6% but inflation is 3%, your real purchasing power grows at approximately 2.9% per year. Over long periods, inflation significantly reduces the real value of nominal gains. High-growth investments (shares, property) generally outpace inflation; cash savings may not.
Where these figures come from
Savings and interest figures on this page are drawn from the Reserve Bank of Australia (cash rate and published deposit averages), APRA (the deposit-taker regulator), and ASIC MoneySmart (consumer guidance).
- RBA cash rate — RBA — Cash Rate.
- Deposit interest-rate data — RBA — Retail Deposit and Investment Rates (F4).
- Financial Claims Scheme (deposit guarantee up to $250k) — APRA — Financial Claims Scheme.
- Compound interest & savings strategy — ASIC MoneySmart — Saving.
- Inflation & CPI — ABS — Consumer Price Index.
Last checked: April 2026. Rates and thresholds are reviewed against the source of record each November, when annual adjustments for the following tax year are published.