What shall we calculate?

What CalcWize is for

CalcWize helps you frame everyday financial and practical questions before you take them to a professional. Could you afford this house? How much would extra mortgage repayments save you over thirty years? Is your retirement plan on track? What does a 5% raise actually look like after tax? The calculators give you a clear set of numbers — a starting point you can take to a financial advisor, accountant, or mortgage broker for a real conversation.

Each calculator opens with a short explainer of what it's for, what assumptions it uses, and what it explicitly does not model. The point is to set expectations honestly: these are estimates, not advice. They're useful for planning, comparing, and pressure-testing — not for filing a tax return or signing a loan.

Money calculators

Seven tools cover the common money decisions: a monthly budget planner with the 50 / 30 / 20 rule built in, a loan / amortisation calculator with extra-payment modelling, a home affordability calculator that uses debt-to-income caps and country-specific property-tax assumptions, a compound-interest projector for long-term saving, a retirement planner with an inflation-adjusted "today's money" toggle, an income-tax estimator with current brackets for over twenty countries, and an investment ROI / CAGR calculator that lets you compare returns across different holding periods on equal footing.

• Monthly 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 Repayment Calculator — 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.
• Home Affordability Calculator — 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 Calculator — 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.
• Income 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 Calculator — Calculate total return and annualised growth (CAGR) on any investment. Compare options on equal footing across different holding periods.
• Salary & Paycheck Calculator — Convert an annual salary to monthly, weekly, and hourly pay, and apply an effective tax rate to estimate take-home pay.

Car & vehicle calculators

Buying a car is one of the biggest everyday purchases there is. Four tools cover the whole decision: how much car you can afford on the 20/4/10 rule, the real cost of an auto loan, whether to lease or buy, and the true cost of ownership once depreciation and running costs are counted.

• Car Affordability Calculator — 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 Calculator — 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 Calculator — Compare the true cost of leasing versus financing the same car over the same period, including resale value, to see which is genuinely cheaper.
• Car Cost of Ownership Calculator — 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 calculators

Four tools for getting out of debt and building a cushion: compare debt-payoff strategies, see how long a credit card really takes to clear, plan toward a savings goal, and size the emergency fund that should come before everything else.

• Debt Payoff Calculator — List your debts and compare the snowball and avalanche payoff methods — which clears your debt fastest and with the least interest.
• Credit Card Payoff Calculator — 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 Calculator — 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 Calculator — Size your emergency fund in months of essential expenses, see how covered you are today, and how long to reach a safe target.

Conversion tools

Two converters for everyday cross-system maths: a currency converter that uses indicative reference rates for travel, shopping, or sizing up an offer in another currency, and a unit converter for length, weight, volume, temperature, time, and speed — recipes, DIY, travel, or any time someone hands you a number in the wrong system.

• 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.

Daily-life calculators

Three small tools you reach for outside of money: tip and bill-splitting (with an optional photo-scan mode for restaurant receipts), BMI in metric or imperial with the standard WHO categories, and a full keyboard-friendly scientific calculator with trig, logs, factorials, and exponentiation for homework or quick engineering checks.

• Tip Calculator & Bill Splitter — Calculate the tip on a restaurant bill and split the total across N people. Round-up control included.
• BMI Calculator — Calculate body-mass index from height and weight in metric or imperial units. Standard WHO categories included. Screening, not diagnosis.
• Scientific Calculator — A full scientific calculator with sin/cos/tan, log/ln, square root, factorials, and exponentiation. Type or click — your choice.
• Percentage Calculator — 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 Calculator — 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 Calculator — 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.
• TDEE & Calorie Calculator — Estimate your daily calorie burn (TDEE) from the Mifflin–St Jeor equation and activity level, with targets to maintain, lose, or gain weight.

Guides & reading

Want the ideas behind the numbers? These plain-English guides explain the concepts the calculators rest on — how loan amortisation works, why compounding rewards starting early, what the 4% rule really promises, how the main budgeting methods compare, and more.

• How Loan Amortisation Actually Works — Your loan payment never changes, but the split between interest and principal shifts every month. Here is why early payments feel like treading water — and how to fix it.
• Compound Interest: Why Time Beats Timing — Compound interest rewards patience more than cleverness. Here is how interest-on-interest works, why the last decade does the heavy lifting, and what quietly works against you.
• The 4% Rule, and the Case Against It — The 4% rule is the most quoted number in retirement planning. Here is where it came from, what it actually promises, and why many planners now treat it with caution.
• Five Budgeting Methods, Honestly Compared — There is no single best budget — only the one you will actually keep. Here are five popular methods, who each one suits, and where each one quietly falls apart.
• How Much House Can You Really Afford? — The maximum a bank will lend you is a ceiling, not a target. Here are the costs a mortgage payment hides and a saner way to set your own limit.
• Marginal vs Effective Tax Rates Explained — A raise into a higher tax bracket will not leave you worse off. Here is why brackets are marginal, what your effective rate really is, and when each number matters.
• Buying a Car: How to Get the Numbers Right — How to set a car budget, choose new vs used, finance sensibly, and weigh the true cost of ownership — without being steered by the monthly payment.
• Debt Snowball vs Avalanche: Which Pays Off Debt Faster? — The avalanche saves the most interest; the snowball keeps you motivated. Here is how each method works, when the gap actually matters, and how to choose.
• How Big Should Your Emergency Fund Be? — Three months, six, or twelve? How to size an emergency fund on your real essentials, where to keep it, and why it comes before investing or extra debt payments.
• Gross vs Net Pay: What Actually Lands in Your Account — Why your take-home is smaller than your salary, what the deductions are, and how to compare a salaried offer with an hourly rate on equal terms.

Privacy & how your data is handled

Every input you type into a CalcWize calculator stays in your browser's local storage on this device. There is no account, no server-side database, no analytics tracking individual values, and no cookie that follows you to other sites. If you clear your browser data, the saved scenarios go with it — that's the trade-off for not having a server holding them. The full details are in our Privacy Policy.

CalcWize displays Google AdSense advertising on calculator result pages to keep the tools free. Cookie consent is asked on first visit, and you can decline and continue using every calculator with no functional change beyond not seeing ads.

Translations

CalcWize is currently available in 21 languages including English, Spanish, French, Portuguese (Brazil), German, Dutch, Italian, Swedish, Romanian, Bulgarian, Russian, Ukrainian, Korean, Japanese, Mandarin Chinese (simplified and traditional), Cantonese, Indonesian, Malay, Thai, and Hindi. The interface translations are in beta — you can switch language from the topbar at any time. The long-form explainer pages on each calculator are now also available in all supported languages.