Calculators You Can Check

Show the working, not just the answer

Most calculators hand you one figure and stop. CalcEezy shows how it got there. A mortgage result comes with the full amortisation schedule and what a rate rise would cost each month. A take-home pay result breaks out every bracket, levy and offset separately. An NPV result tells you the discount rate it assumed and the IRR that would make the project break even. A novated lease result shows which FBT treatment it applied and why. If you cannot see the working, you cannot check it — and you should be able to check it.

How we keep it accurate

The calculators split into two kinds, and they are checked in two different ways. Rate-driven tools — take-home pay, HECS-HELP, novated leasing, borrowing power — depend on figures a government publishes and changes, so they are only as good as their source. Formula-driven tools — mortgages, compound interest, NPV and IRR, growth rates, margins, runway — rest on standard finance mathematics that does not change, so what matters is that the formula is stated and implemented correctly.

We also correct things when they are wrong. Recent corrections include moving HECS-HELP to the 2026–27 marginal repayment system, adding the Low Income Tax Offset, fixing the Medicare levy low-income threshold, updating the Medicare Levy Surcharge tiers, and correcting the novated lease GST credit so it is calculated on the vehicle’s base value rather than the drive-away price — because registration, CTP and stamp duty carry no GST.

The formulas behind the numbers

These are the formulas the calculators actually implement, not simplified illustrations. Each is standard finance mathematics you can check against any textbook or spreadsheet.

P is the amount borrowed, i the periodic rate (annual rate ÷ 12) and n the number of payments. On a $700,000 loan at 5.90% over 30 years this returns $4,152 a month — the same figure the mortgage calculator gives. The amortisation schedule then applies each payment to interest first and principal second.

Instead of a closed-form future-value formula, the compound interest calculator steps through every period, so you can choose the compounding frequency and add regular contributions. Contributions are applied at the end of each period.

C_t is the cash flow in period t, with the initial outlay entered as a negative at t = 0, and r is the discount rate. IRR has no algebraic solution, so it is found numerically by bisection to a tolerance of 0.0001. Where the cash flows never change sign no IRR exists, and the calculator says so rather than inventing one.

Growing $100,000 to $200,000 over five years is a CAGR of 14.87%. The business tools follow the same principle: runway is cash divided by net monthly burn, gross margin is (revenue − cost of goods) divided by revenue, and the cash conversion cycle is days inventory plus days receivable minus days payable.

Official rate sources, country by country

This section covers the rate-driven calculators only — the ones whose answer depends on a figure a government sets. Each country below lists the authority that publishes those rates, so you can check any number at its source. If a figure here disagrees with the authority, the authority is right and we want to hear about it. The formula-driven calculators are covered above.

Rates change and some countries publish mid-year. Where our figure is out of date we want to know — a correction report with the source link is the fastest way to get it fixed.

Found something wrong?

Calculation-error reports are the ones we act on fastest. If a figure looks wrong, tell us — include the inputs you used and we will check it against the official source and correct it if needed. We would rather be told than be wrong.

What you can calculate

Thirty-two calculators across six areas. Browse the full list, or start here:

Take-home pay (34 countries) · Australia · USA · UK · Canada · New Zealand · Take-home by salary · HECS-HELP repayment · Hourly to salary & work hours · Year-to-date pay

Mortgage repayments · Borrowing power · Rent vs buy · Mortgage switching · Cash-out refinance

Novated lease · $60k EV lease · $70k EV lease · Car loan · Total cost of ownership

Budget planner · Credit card payoff · Debt snowball · Loan payoff · Compare loans

Compound interest · Retirement · Investment return · Bond return · Inflation

Profit margin · Business ROI · Runway · CAC & LTV · Cash conversion cycle · Growth rate / CAGR · NPV & IRR

Percentage · Days between dates

Private by design

Every calculation happens in your browser using JavaScript. Your salary, loan balance and other figures are never sent to a server, never stored and never shared. There are no accounts and no sign-up, and most calculators keep working if you lose your connection after the page loads. See our privacy policy for detail.

What this is not

CalcEezy provides general information, not financial, tax or legal advice. Results are estimates based on published rates and standard assumptions, and they exclude circumstances we cannot know — other income, deductions, offsets you may be entitled to, and changes announced after our last update. Confirm anything important with the ATO, a registered tax agent or a licensed adviser before acting on it.

Australian rates last reviewed 31 July 2026 against the source pages listed above. Questions or corrections: contact us.