Smart Financial Calculators

Drag the sliders and watch the numbers — and the charts — update instantly. Every tool is free and runs entirely in your browser.

Loan details

Worked example: $250,000 at 6.5% costs about $1,580 a month over 30 years and $318,900 in total interest. Over 20 years the payment rises to about $1,864 — roughly 18% more each month — while total interest falls to about $197,300, a saving near $121,500. Drag the term slider to reproduce it.

Assumptions

  • A fixed interest rate for the whole term, and equal monthly payments (a standard amortising loan).
  • Interest compounds monthly at the annual rate ÷ 12; payments are made at the end of each month.
  • No fees, insurance, taxes, early-repayment penalties or rate changes are included, so a real lender's APR and total cost will be higher.
  • Results are estimates, not a quote or an offer of credit.

See how the EMI formula works →

Monthly payment
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Total interest
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Total paid
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What you repay: principal vs interest

Remaining balance over time

Investment plan

Context: long-run studies of broad developed stock markets — for example the annual Global Investment Returns Yearbook (Dimson, Marsh & Staunton) — put average real (after-inflation) equity returns in the mid single digits over more than a century, with enormous variation between decades and countries. Pick your own rate deliberately; the default here is an illustration, not a forecast.
Future value
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You contribute
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Growth earned
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Projected growth

Assumptions behind these numbers

  • Contribution timing: each monthly contribution is added at the end of the month (an ordinary annuity), so the first one earns no return in the month it is made.
  • Compounding: monthly. The annual rate you choose is divided by 12 and applied every month, so the effective yearly growth is slightly above the headline rate.
  • Excluded: fees, taxes, and inflation. The result is a nominal figure — it does not tell you what it will buy. Subtract expected inflation from your return to see it in today's money.
  • Not guaranteed: real returns arrive unevenly and can be negative for years at a time. This is arithmetic on a constant rate, not a forecast.
  • Currency-neutral: figures are labelled in dollars, but the maths is identical in any currency — read “$” as your own.

See the formula worked through step by step →

Your retirement picture

Today's money vs future money. You enter the spending you'd want if you retired today. Inflation is then applied to work out the larger, nominal amount that buys the same basket at your retirement date — that bigger number is what your savings actually have to reach.
Goal in today's money
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25× your annual spending
Same goal at retirement
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Projected savings (nominal)
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Shortfall or surplus
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Savings projection vs the rising goal

Assumptions this projection uses

    The 25× / 4% figure is a rough historical planning guideline, not a guarantee. It comes from studies of historical US market returns — most famously the 1998 “Trinity study” and William Bengen's 1994 work — which asked what fixed withdrawal rate would have survived past 30-year retirements using US stock and bond data. It is not a law of finance: it assumes a 30-year horizon, a specific asset mix, US historical returns, and no state pension, annuity, property or unusual costs. Later research has argued for both higher and lower safe rates depending on valuations, fees, country and retirement length. Treat the result as a rough target to react to, not a number to bet a retirement on, and see how inflation affects retirement.

    Your income

    How the 50/30/20 rule works

    • 50% Needs — rent or mortgage, groceries, utilities, transport, insurance premiums, minimum debt payments.
    • 30% Wants — dining out, streaming, travel, hobbies, upgrades you could live without.
    • 20% Savings & debt — emergency fund, investments, retirement, and extra debt payments beyond minimums.

    If needs exceed 50% where you live, trim the wants share first — never the savings share.

    Your monthly split

    Needs · 50%
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    Wants · 30%
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    Save · 20%
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    Saving — a year at this rate. Invested at a steady 8% a year with monthly compounding and end-of-month contributions, that would grow to roughly — after 10 years — before fees, taxes and inflation, and assuming a return no one can promise.