Free calculators covering mortgage, investment, superannuation, retirement, loans, tax, and more — all built for Australian laws, rates, and regulations. No US-specific calculators (no 401k, FHA, VA, HELOC, Roth IRA, Social Security).
🚫 US-only calculators not built: FHA Loan, VA Mortgage, HELOC, 401(k), Roth IRA, Required Minimum Distribution (RMD), Social Security — these are US tax/government programs with no Australian equivalent. Australian equivalents: Superannuation, Age Pension, Home Equity Loan.
| Your question | Use this |
|---|---|
| What will my savings grow to? | Compound Interest Calculator |
| How big should my emergency fund be? | Budget Calculator |
| What will my loan repayments be? | Loan Calculator |
| Which debt should I pay off first? | Debt Payoff Calculator |
| Will I have enough to retire? | Retirement Calculator |
| How much super will I have at 65? | Superannuation Calculator |
| Do I qualify for the Age Pension? | Age Pension Calculator |
| What's this worth in today's dollars? | Inflation Calculator |
| Should I lease or buy the car? | Auto Lease Calculator |
| How much GST do I add or remove? | GST Calculator |
Compound interest earns returns on your returns. In the early years the balance grows mostly because you are adding to it; the interest is small because the balance is small. That flat stretch is where most people conclude it isn't working and stop.
The steepening happens because the balance grew, not because the mechanism changed. At some point the interest earned in a year exceeds what you contributed that year — the crossover, and it typically arrives a decade or more in.
Gain 50% then lose 50% and your arithmetic average is zero — but $100,000 becomes $150,000, then $75,000. You are down a quarter while "averaging" nothing.
What compounding actually follows is the geometric mean, which is always lower when returns vary. Recovering a 50% loss requires a 100% gain. Losses and gains are not symmetrical, which is why avoiding large drawdowns matters more to the long run than capturing every upswing.
Real after-tax return ≈ (Nominal rate × (1 − marginal rate)) − Inflation
Interest in a savings account is generally assessable income in the year it is credited, taxed at your marginal rate. Inflation then reduces what the balance buys. A 5% account, at a mid-range marginal rate, during 3% inflation, delivers a real after-tax return close to zero.
The balance rises every year and buys the same groceries. This is not an argument against saving — it is an argument for knowing what a projection is actually showing you.
Paying off a debt charging a high rate returns exactly that rate, guaranteed, tax free. No savings account competes, and few investments do so reliably.
This is why the conventional sequence begins with a small emergency buffer, then high-interest debt, then a fuller emergency fund, then longer-term investing. Without the starter buffer, the first setback goes onto a credit card and undoes everything.
Budgets fail on the expenses that are entirely predictable but not monthly — registration, insurance premiums, school fees, Christmas. Each arrives as a surprise despite being on the calendar every year.
A sinking fund converts an annual cost into a monthly one. Total everything irregular across the next twelve months, divide by twelve, and treat the result as a fixed monthly cost. Most people find the figure larger than expected, which is exactly why the budget kept breaking.
Calculators: Budget · Discount · Currency
Guides: Your first budget · Creating a budget · Emergency funds · Family budgets · Weekly budgeting
Two orderings dominate. Avalanche targets the highest interest rate first and mathematically minimises total interest. Snowball targets the smallest balance first and produces faster psychological wins. Both pay minimums on everything; they differ only in where the extra dollar goes.
Consolidating into a mortgage lowers the repayment and is the option that most often ends badly — you have converted unsecured debt into debt secured against your home, usually over a much longer term.
Calculators: Debt Payoff · Credit Card Payoff · Debt Consolidation · Personal Loan
Guides: Credit card debt · Debt consolidation · Personal loans
The three levers are how much you contribute, how long it compounds, and what you pay in fees. You control the third entirely, and it is the one people dismiss because the percentage looks small.
Every projection you will see assumes a constant annual return. Real returns arrive unevenly, and no calculator models tax, fees, or your own behaviour during a downturn. Run any projection three times — pessimistic, moderate, optimistic — and treat the spread as the honest answer.
Calculators: Compound Interest · Investment · Interest · Inflation
Guides: How compounding works · Compound vs simple interest · Volatility drag · Inflation and real returns
While you accumulate, a market fall is survivable — you hold the same units and keep buying. Once you are drawing an income, the arithmetic inverts: a fall early in retirement means selling units at depressed prices, and those units are permanently gone.
This is sequencing risk, and it is why a retirement strategy is not an accumulation strategy with withdrawals attached. Published retirement benchmarks also generally assume you own your home outright and receive a part Age Pension.
Calculators: Retirement · Superannuation · Age Pension · Annuity
Guides: How much super should I have? · Account-based pensions · Accessing your super · Age Pension explained · Fees and your final balance
Every comparison of lease, loan, and cash focuses on finance costs. The largest cost of most cars is neither — it is depreciation, and it is identical regardless of how you pay. Financing determines who bears the cash flow and when; it does not change the underlying loss.
Calculators: Auto Loan · Auto Lease · Cash Back vs Low Interest
Guides: Lease vs buy
Markup is calculated on cost. Margin is calculated on the selling price. They are not interchangeable — a 50% markup produces a 33.3% margin, and confusing them systematically flatters the business.
Calculators: Business Loan · Margin · GST · Commission · Depreciation
Guides: Business loans · Margin vs markup · GST explained
Sometimes the arithmetic simply does not balance, and no budgeting technique changes that. If essential costs exceed your income, the problem is not discipline.
Australian credit providers have hardship obligations, and requesting a hardship variation early — before arrears accumulate — gives you more options. Free, independent, confidential financial counselling is available through the National Debt Helpline on 1800 007 007. Financial counsellors are not lenders and are not selling anything.
Be cautious of commercial services charging fees to negotiate on your behalf or arrange a debt agreement. The same assistance is available at no cost.
What is the difference between compound interest and simple interest?
Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus all previously accumulated interest, so returns are earned on returns. Over long periods the two diverge substantially, which is why compounding is described as accelerating over time.
Should I pay off debt or invest my savings?
Clearing a debt returns exactly the interest rate on that debt, guaranteed and tax free. Few investments offer a comparable certain return. A common sequence is to build a small emergency buffer first, then clear high-interest debt, then build a fuller emergency fund, then invest. Your circumstances may justify a different order.
How large should my emergency fund be?
Three to six months of essential expenses is a widely used starting reference. What actually determines the right figure is how likely your income is to stop and how long it would take to replace. Sole traders, casual workers, single-income households, and people in cyclical industries generally need more.
Is a savings account keeping up with inflation?
Often not, once tax is included. Interest is generally assessable income in the year it is credited and taxed at your marginal rate, while inflation reduces what the balance buys. A nominal rate of five per cent during three per cent inflation can deliver a real after-tax return close to zero.
What is a comparison rate and why does it matter?
A comparison rate expresses the cost of a loan on a reducing-balance basis with most fees included, so that offers can be compared honestly. It is important because some loans are quoted as a flat rate, calculated on the original amount borrowed for the whole term, which can be close to double the equivalent reducing-balance rate.
Do fees really make much difference to my superannuation?
Yes. Fees are deducted from the balance, so money removed early also forgoes everything it would have earned across the remaining decades. A difference of a single percentage point in annual fees, sustained across a working life, can consume a substantial share of a final balance.
What is sequencing risk?
Sequencing risk is the risk that poor investment returns arrive early in retirement, while you are drawing an income. Selling units at depressed prices to fund payments permanently removes them, so a later market recovery operates on a smaller balance. The same returns arriving in a different order produce a materially different outcome.
Is negative gearing a strategy on its own?
No. Negative gearing means the investment makes a loss each year, and that loss can generally be offset against your other assessable income, recovering a portion at your marginal rate. You remain out of pocket for the remainder. It only makes sense if capital growth is expected to exceed the accumulated losses.
Should I consolidate my debts into my mortgage?
It lowers the monthly repayment, and it converts unsecured debt into debt secured against your home. A credit card default damages your credit file; a mortgage default can cost you the house. A lower rate over twenty-five years can also cost more in total interest than a higher rate over three.
Are these calculators financial advice?
No. They are educational tools producing estimates based on the information you enter and general assumptions. They cannot account for your circumstances, and they do not model tax, fees, variable returns, or your own behaviour. Speak with a licensed financial adviser before making significant financial decisions.
Where a figure changes — interest rates, inflation, contribution caps, Age Pension thresholds — we point you to the authority rather than restating a number that may have moved.
Read more about how we build and check our calculators, or about who writes this site.
Important: MegaCalcOnline provides general information and educational calculators only. Nothing here is financial, tax, or legal advice, and none of it takes your personal circumstances into account. Every projection assumes constant returns and ignores fees, tax, and market volatility. Speak with a licensed financial adviser before making significant financial decisions. If you are under financial pressure, free confidential financial counselling is available through the National Debt Helpline on 1800 007 007.
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