All calculators

Money & finance

Plan a budget, size a loan or mortgage, project savings and retirement, estimate tax and take-home pay, and measure investment returns — the decisions where getting the numbers straight matters most.

• Budget Planner — Map your monthly income and expenses, see what's left, and check it against the 50/30/20 needs/wants/savings rule.
• Loan / Amortisation — Work out the monthly payment, total interest, and payoff date on any loan. Add an extra-payment to see how many months and how much interest you save.
• Mortgage Affordability — Work back from your income, debts, and down payment to a sane home purchase price using debt-to-income limits and country-specific tax assumptions.
• Compound Interest — See how your starting balance plus monthly contributions grow over time at a given annual rate. Includes a year-by-year breakdown of contributions vs. interest earned.
• Retirement Planner — Project your retirement savings, see your safe annual withdrawal, and find the gap to your target. Inflation-adjusted "today's money" toggle included.
• Tax Estimator — Estimate income tax across 14 countries using each authority's current brackets. Includes retirement deductions, fringe benefits, age rebates, and refund-or-owe.
• Investment ROI — Calculate total return and annualised growth (CAGR) on any investment. Compare options on equal footing across different holding periods.
• Salary / Paycheck — Convert an annual salary to monthly, weekly, and hourly pay, and apply an effective tax rate to estimate take-home pay.

Cars

Everything around buying and running a car: what you can actually afford, the real cost of a finance deal, lease versus buy, and the total cost of ownership once depreciation and running costs are counted.

• Car Affordability — Find the car price you can actually afford with the 20/4/10 rule: 20% down, a 4-year loan, and total car costs under 10% of your income.
• Car Loan — Work out a car loan’s monthly payment, total interest, and amount financed — including down payment, trade-in, sales tax, and dealer fees.
• Lease vs Buy — Compare the true cost of leasing versus financing the same car over the same period, including resale value, to see which is genuinely cheaper.
• Cost of Ownership — Add up what a car really costs — depreciation, fuel, insurance, maintenance, and registration — over the years you own it, per month and per mile.

Debt & savings

Get out of debt and build a cushion: compare payoff strategies, see how long a credit card really takes, plan toward a savings goal, and size the emergency fund that comes before everything else.

• Debt Payoff — List your debts and compare the snowball and avalanche payoff methods — which clears your debt fastest and with the least interest.
• Credit Card Payoff — See how long a credit card takes to clear at a set monthly payment, and how much interest you’ll pay. Find a payment that actually makes progress.
• Savings Goal — Find out how long it takes to reach a savings goal at your monthly contribution and return rate, and how much of the total is interest.
• Emergency Fund — Size your emergency fund in months of essential expenses, see how covered you are today, and how long to reach a safe target.

Conversions

Switch between major currencies at indicative rates, or convert length, weight, volume, temperature, and more — handy for travel, recipes, and shopping across systems.

• Currency Converter — Convert between major currencies using indicative rates. Good for travel, shopping, or quick estimates — not for booking a real trade.
• Unit Converter — Switch between metric and imperial units in either direction — recipes, travel, DIY, or any time someone hands you a number in the wrong system.

Everyday maths

The quick calculations that come up all the time: tips and bill splits, percentages, your exact age and the gap between dates, sales tax or VAT, and a full scientific calculator.

• Tip & Split — Calculate the tip on a restaurant bill and split the total across N people. Round-up control included.
• Scientific — A full scientific calculator with sin/cos/tan, log/ln, square root, factorials, and exponentiation. Type or click — your choice.
• Percentage — Find a percentage of a number, what percent one value is of another, and the percent change between two numbers — fast, with worked examples.
• Age & Date — Calculate your exact age in years, months, and days, the days to your next birthday, and the difference between any two dates.
• Sales Tax / VAT — Add sales tax or VAT to a price, or remove it from a tax-inclusive total, to see the net amount, the tax, and the total.

Health

Quick body metrics: your Body Mass Index and screening category, and your daily calorie needs (TDEE) with targets for maintaining, losing, or gaining weight. A starting point, not medical advice.

• BMI / Health — Calculate body-mass index from height and weight in metric or imperial units. Standard WHO categories included. Screening, not diagnosis.
• Calorie / TDEE — Estimate your daily calorie burn (TDEE) from the Mifflin–St Jeor equation and activity level, with targets to maintain, lose, or gain weight.

Learn the ideas behind them

Want the reasoning, not just the result? The guides explain the concepts in plain English, and the methodology page sets out the formulas, sources, and review process behind every tool.