Finance & Money Calculators
14 free finance & money calculators, each explaining its formula.
Loans, savings, interest, salary and the arithmetic of everyday money decisions, worked through step by step rather than hidden behind a black box.
Compound Interest Calculator
Compounding is interest earning interest. Over short periods it is barely noticeable; over decades it does most of the work.…
Finance & MoneyLoan Calculator
The monthly payment is the number lenders advertise. The total interest is the number that decides whether the loan is good value.…
Finance & MoneyMortgage Calculator
A mortgage is usually the largest loan anyone takes and the one where small differences in rate compound into very large amounts o…
Finance & MoneyCredit Card Payoff Calculator
Minimum payments are calculated to be affordable, not to clear the debt. On a typical card they can keep a balance alive for well …
Finance & MoneySavings Goal Calculator
Turn a vague intention into a monthly number — the only form a savings goal survives contact with real life in.…
Finance & MoneyInflation Calculator
Inflation is the reason a salary that has not changed in five years is a pay cut.…
Finance & MoneyTip Calculator
Quick tip maths, plus a per-person split and a note on what to do when service is already on the bill.…
Finance & MoneyDiscount Calculator
Also handles stacked discounts — where '30% off then an extra 20% off' is not 50% off, and the gap is bigger than most people assu…
Finance & MoneySales Tax & VAT Calculator
The common mistake is removing VAT by subtracting the percentage. Taking 20% off a VAT-inclusive price does not give you the net p…
Finance & MoneySalary Converter
Comparing a contract rate with a salaried job means converting both to the same basis — and remembering that paid leave is worth r…
Finance & MoneySimple Interest Calculator
Simple interest is charged only on the original sum. It still appears in short-term loans, bonds and some flat-rate credit agreeme…
Finance & MoneyRule of 72 Calculator
A mental shortcut accurate enough for most purposes: divide 72 by the rate and you have the doubling time in years.…
Finance & MoneyROI Calculator
A 50% total return sounds impressive until you learn it took twelve years. Annualising is what makes returns comparable.…
Finance & MoneyBreak Even Calculator
The break-even point is the sales level at which a business stops losing money. Every unit after it contributes to profit.…
About this section
Almost all everyday financial arithmetic reduces to a small number of formulas applied honestly. Compound interest, amortisation, percentage change and present value cover the overwhelming majority of the calculations people actually need, and the reason financial products feel opaque is rarely that the mathematics is difficult.
It is usually that the relevant number is not the advertised one. A loan's monthly payment is advertised; its total interest is not. An exchange's commission is advertised; its spread is not. A flat interest rate sounds lower than an APR because it is calculated on the original balance rather than the falling one, and the effective cost is roughly double the headline. In every case the arithmetic is simple and the presentation is doing the work.
The calculators here are built to show both figures. Where a monthly payment is produced, the total cost is produced alongside it. Where a discount is applied, the effective percentage is shown next to the naive sum. Where a fee is charged on both sides of a transaction, the break-even price appears as its own line.
These are estimates and they exclude what they cannot know: your provider's exact fee schedule, your tax position, rounding conventions and eligibility rules. Two lenders applying the same nominal rate can legitimately produce different figures from ours. Treat a result as a way to prepare the right question, not as a quotation.