Calculator library

Formula-Backed Calculators

Browse finance, budget, tax, business, investing, math, economics, and health calculators built with transparent formulas, interpreted results, and downloadable workbook support where useful.

Use the search and category filters below to find the right calculator for your decision — many tools include explanations, scenario comparisons, charts, and downloadable Excel workbooks.

44 calculators

FinanceMortgage CalculatorEstimate monthly payments, interest, taxes, insurance, PMI, and amortization using practical home-loan assumptions.Best for: Sizing up a home purchase before talking to a lender.FormulaXLSXChartsScenariosAmortizationAdvancedRegion modesOpen calculator FinanceCompound Interest CalculatorSee how savings grow as interest earns interest, with adjustable contributions and compounding frequency.Best for: Understanding the long-run power of compounding.FormulaChartsOpen calculator InvestingInvestment CalculatorProject lump-sum and regular-contribution growth, plan a goal, and solve future vs present value, with fees and inflation.Best for: Projecting how a lump sum or monthly contributions may grow, and the time value of money.FormulaXLSXChartsScenariosAdvancedOpen calculator InvestingRegular Investment CalculatorProject how regular monthly contributions grow over time — SIP-style investing, dollar-cost averaging, inflation-adjusted value, and long-term goals.Best for: Monthly investing, SIP, and dollar-cost averaging.FormulaChartsOpen calculator InvestingRetirement Withdrawal CalculatorEstimate how long savings last under regular withdrawals (SWP) — drawdown, safe withdrawal rate, inflation, and a year-by-year schedule.Best for: Retirement income, portfolio drawdown, and how long your money will last.FormulaXLSXChartsOpen calculator MathStandard Deviation CalculatorSample and population standard deviation, plus variance, mean, median, quartiles, z-scores, outliers, and confidence intervals.Best for: Analysing the spread, shape, and outliers of a dataset, with every statistic at once.FormulaXLSXChartsScenariosOpen calculator BusinessProfit Margin CalculatorWork out gross, contribution, operating, and net margin, with target pricing, break-even, scenarios, and SKU comparison.Best for: Knowing whether you are actually profitable — and where the margin leaks.FormulaXLSXScenariosAdvancedOpen calculator TaxIncome Tax CalculatorEstimate income tax with custom progressive bands, a sourced US federal mode, refund or amount owed, and scenario comparison.Best for: Progressive tax, refund estimates, and take-home pay for any country.FormulaXLSXScenariosAdvancedRegion modesOpen calculator FinanceLoan CalculatorWork out the monthly payment, total interest, and payoff date for any fixed-rate loan from the amount, rate, and term.Best for: A quick payment estimate for any kind of loan.FormulaXLSXAmortizationOpen calculator Budget & CreditCredit Card Payoff CalculatorPlan up to 20 cards with issuer-style minimums, promo APRs, five payoff orders, and a balance-transfer scenario.Best for: Finding a payment that clears the cards and escaping the minimum-payment trap.FormulaXLSXScenariosOpen calculator BusinessBreak-Even ROAS CalculatorWork out break-even and target ROAS from your real margins, plus max CAC, break-even MER, and ad budgets.Best for: Knowing the ROAS floor your margins demand — and the target that actually hits your profit goal.FormulaXLSXScenariosOpen calculator TaxVAT/GST CalculatorAdd or remove VAT, GST, or HST from a price, solve tax-inclusive and tax-exclusive values, and build mixed-rate invoices.Best for: VAT, GST, and invoice tax breakdowns in any currency.FormulaXLSXRegion modesOpen calculator FinanceMortgage Refinance CalculatorCompare your current mortgage to a new rate and term — monthly saving and break-even time on closing costs.Best for: Deciding whether refinancing is worth the closing costs.FormulaXLSXScenariosAmortizationOpen calculator FinanceAmortization Schedule CalculatorBuild a full payment-by-payment schedule showing how each instalment splits between principal and interest.Best for: Seeing the year-by-year breakdown of any fixed loan.FormulaXLSXAmortizationOpen calculator FinancePersonal Loan CalculatorEstimate repayments on an unsecured personal loan and see how the rate and term change what you pay overall.Best for: Comparing personal-loan offers side by side.FormulaXLSXAmortizationOpen calculator FinanceAuto Loan CalculatorCalculate a car-loan payment from price, down payment, trade-in, rate, and term, including the total cost of financing.Best for: Budgeting the monthly cost of a vehicle.FormulaXLSXAmortizationOpen calculator FinanceAPR CalculatorTurn a loan rate plus fees into the true annual percentage rate so you can compare offers on equal terms.Best for: Spotting the real cost behind a low headline rate.FormulaXLSXScenariosOpen calculator FinanceSavings CalculatorProject a savings balance or solve the deposit needed for a goal, with APR/APY, tax, and inflation.Best for: Forecasting savings growth or planning a savings goal.FormulaXLSXChartsOpen calculator FinanceRetirement CalculatorProject your retirement pot from current savings, contributions, and growth, and gauge whether it meets your goal.Best for: Checking if your saving rate is on track.FormulaXLSXChartsOpen calculator Finance401(k) CalculatorProject a 401(k) balance with employer match, 2026 IRS limits, fees, inflation, and a match maximiser.Best for: Maximising your match and projecting your balance.FormulaXLSXChartsAdvancedOpen calculator EconomicsFinancial Needs Pyramid CalculatorScore five layers of your financial foundation — survival, safety, support, growth, and freedom — with a stress test and what-if simulator.Best for: Seeing which money layer to strengthen first before chasing higher-level goals.FormulaXLSXChartsScenariosAdvancedOpen calculator InvestingROI CalculatorSimple, date-based, and net ROI with annualised ROI (CAGR), a reverse target solver, and a two-investment comparison.Best for: Judging whether an investment paid off, its annual growth rate, and comparing two options.FormulaXLSXChartsScenariosOpen calculator InvestingDividend Reinvestment CalculatorModel DRIP vs cash dividends, after-tax reinvestment, yield on cost, and a dividend income goal solver.Best for: Dividend income planning and the long-run effect of reinvesting.FormulaXLSXChartsScenariosOpen calculator TaxSalary & Take-Home Pay CalculatorEstimate take-home pay with sourced payroll models for the US, India, UK, Canada, and Australia, plus a net-to-gross solver.Best for: Seeing what actually lands in your account from salary, hourly, or CTC pay.FormulaXLSXScenariosAdvancedOpen calculator Budget & CreditBudget CalculatorBuild a monthly and annual budget in simple or 65-line advanced mode, with savings rate, ratios, and a health score.Best for: Seeing your real monthly surplus or deficit and where the money goes.FormulaXLSXAdvancedOpen calculator Budget & Credit50/30/20 Budget CalculatorSplit take-home pay into 50% needs, 30% wants, and 20% savings, compare your real spending, and test alternative ratios.Best for: Applying the 50/30/20 rule to your actual spending, not just your income.FormulaXLSXScenariosOpen calculator Budget & CreditNet Worth CalculatorBuild a personal balance sheet — quick or 78-line detailed — with liquid and tangible net worth and debt analysis.Best for: Seeing what you own, what you owe, and how accessible your wealth really is.FormulaXLSXAdvancedOpen calculator Budget & CreditDebt Payoff CalculatorSimulate up to 20 debts with snowball, avalanche, custom, or hybrid payoff order and find your debt-free date.Best for: Finding your debt-free date and the payoff order that fits you.FormulaXLSXScenariosOpen calculator BusinessMarkup CalculatorPrice from cost across nine modes — markup, target margin, reverse cost ceilings, and ecommerce landed cost after fees.Best for: Setting a selling price from cost — without confusing markup and margin.FormulaXLSXScenariosAdvancedOpen calculator BusinessBreak-Even CalculatorFind units and revenue break-even, contribution margin, target profit, and margin of safety, with sensitivity tables and a chart.Best for: Knowing how much you must sell to not lose money — and how much buffer you have.FormulaXLSXChartsScenariosAdvancedOpen calculator BusinessEcommerce Profit CalculatorSee net profit per order after product costs, fees, shipping, ads, and returns, with break-even price and ROAS.Best for: Seeing what you actually keep per order — and which cost line is eating it.FormulaXLSXScenariosOpen calculator BusinessLTV:CAC CalculatorCalculate CAC, discounted LTV, the LTV:CAC ratio, and CAC payback, with channel-by-channel decisions and scenarios.Best for: Judging whether acquisition spend pays back — and whether it is safe to scale.FormulaXLSXScenariosOpen calculator BusinessPrice Elasticity of Demand CalculatorMeasure price elasticity of demand (midpoint and simple PED) and test how a price change affects revenue and profit.Best for: Deciding whether a price increase or discount will help revenue and profit.FormulaXLSXScenariosAdvancedOpen calculator BusinessAI Agent Cost CalculatorModel per-attempt AI cost, retries, tool calls, caching, and human review to find the real cost per successful task.Best for: Knowing what an AI agent actually costs once retries, failures, and review are included.FormulaOpen calculator MathScientific CalculatorTrigonometry, logarithms, powers, roots, and factorials with correct order of operations, memory registers, history, and keyboard entry.Best for: Trig, logs, powers and roots with the right order of operations.FormulaAdvancedOpen calculator MathPercentage CalculatorSolve X% of Y, what percent X is of Y, reverse percentage, increase/decrease, discounts, and tax, tip, or commission.Best for: Every everyday percentage question in one tool.FormulaXLSXScenariosOpen calculator MathPercentage Change CalculatorWork out percentage increase or decrease, reverse change, loss recovery, percentage points, multi-period change, and CAGR.Best for: Analysing how much a value rose or fell — and what it takes to reverse it.FormulaXLSXScenariosOpen calculator EconomicsDiminishing Returns CalculatorTurn input-output data into total, marginal, and average product and find the point of diminishing returns.Best for: Finding where adding more input stops paying off.FormulaXLSXChartsScenariosAdvancedOpen calculator EconomicsOpportunity Cost CalculatorCompare two choices to see net value, opportunity cost, explicit vs implicit costs, and risk-adjusted scenarios.Best for: Comparing two choices and the value you give up.FormulaXLSXScenariosOpen calculator EconomicsMarginal Utility CalculatorTurn a utility table into total and marginal utility and utility per dollar, and find the satiation point.Best for: Seeing where each extra unit stops being worth it.FormulaXLSXChartsScenariosOpen calculator EconomicsMarket Equilibrium CalculatorSolve equilibrium price and quantity from linear demand and supply, with surplus, a shift simulator, and tax incidence.Best for: Solving equilibrium price, quantity, surplus, and policy interventions.FormulaXLSXChartsScenariosAdvancedOpen calculator HealthBMI CalculatorCalculate BMI in metric or imperial units, see your adult category and healthy-weight range, with clear limitations and a separate under-18 result.Best for: A quick, honest BMI screening check with real limitations explained.FormulaOpen calculator HealthTDEE CalculatorEstimate BMR, TDEE and daily calorie needs with the Mifflin-St Jeor equation, a maintenance range, and calorie scenarios for losing…Best for: Finding a realistic starting-point calorie target before setting a goal.FormulaOpen calculator HealthCalorie Deficit CalculatorCalculate a daily calorie deficit and an adaptive weight-loss timeline range from your TDEE, with a safety-floor warning and a scenario comparison.Best for: Planning a realistic weight-loss timeline with an honest planning range, not one fixed date.FormulaOpen calculator

New here? These six cover the most common decisions across finance, budgeting, business, math, and tax.

FinanceMortgage CalculatorSize up a home purchase — payment, interest, taxes, and insurance.Open calculator Budget & CreditBudget CalculatorSee your monthly surplus, savings rate, and where the money goes.Open calculator BusinessProfit Margin CalculatorFind gross, operating, and net margin, and the price for a target.Open calculator MathPercentage CalculatorPercentages, increases, decreases, and “what percent of” in one place.Open calculator FinanceCompound Interest CalculatorProject how savings or investments grow with compounding over time.Open calculator TaxIncome Tax CalculatorEstimate tax across progressive bands and compare two scenarios.Open calculator

Start with what you want to do

Pick a goal and jump straight to the right set of tools.

Buy or refinance a home

Plan savings or investing

Understand tax and take-home pay

Fix budget and debt

Run a business or store

Solve math & statistics

Learn economics & decisions

Browse by category

Every published category in one place. Open a category for its full set of calculators.

Finance

11 tools

Mortgages, loans, amortization, interest, savings, and retirement planning.

View Finance

Investing

5 tools

Growth, returns, income, compounding, regular investing, and withdrawal planning.

View Investing

Budget & Credit

5 tools

Budgets, debt payoff, credit card payoff, net worth, and personal cash flow.

View Budget & Credit

Business

8 tools

Margins, markup, break-even, ecommerce profit, ROAS, LTV:CAC, and pricing decisions.

View Business

Tax

3 tools

Income tax, VAT/GST, salary, take-home pay, and practical tax estimates.

View Tax

Economics

5 tools

Opportunity cost, marginal utility, diminishing returns, pricing response, and production models.

View Economics

Math

4 tools

Percentages, percentage change, standard deviation, variance, dataset analysis, and a scientific calculator.

View Math

Health

3 tools

BMI, daily calorie needs (TDEE), and a calorie-deficit weight-loss timeline.

View Health

What the badges mean

Formula — Shows the calculation method and a worked example.

XLSX — Downloadable Excel/CSV workbook generated from your inputs.

Charts — Visual breakdown of the result.

Scenarios — Compare different assumptions side by side.

Amortization — Full payment-by-payment schedule.

Region modes — Country-specific labels or assumptions where available.

Advanced — Deeper planner with multiple modes.

Recently improved

What we have upgraded lately — the site is actively maintained.

Not sure which calculator to use?

Quick guidance when two tools look similar.

Mortgage Calculator vs Loan Calculator

Use Mortgage for a home purchase with taxes, insurance, and PMI; use Loan for any general fixed loan.

Budget Calculator vs 50/30/20 Budget Calculator

Budget is a full line-by-line plan; 50/30/20 is a quick needs/wants/savings split.

Profit Margin Calculator vs Markup Calculator

Margin is profit as a share of price; markup is profit as a share of cost.

ROI Calculator vs Investment Calculator

ROI measures a single investment’s return; Investment projects growth from contributions over time.

VAT/GST Calculator vs Income Tax Calculator

VAT/GST works on a price; Income Tax works on earnings and brackets.

Debt Payoff Calculator vs Credit Card Payoff Calculator

Debt Payoff compares snowball vs avalanche across debts; Credit Card focuses on one card and minimum-payment traps.

Frequently asked questions

Choosing a calculator and reading the results.

What calculators are available on Calculator Matters?

Formula-backed calculators across 8 categories — Finance, Investing, Budget & Credit, Business, Tax, Economics, Math and Health — covering 44 tools in total.

How is my data handled when I use a calculator?

Every calculator runs directly in your browser for educational planning, and the figures you enter for a basic calculation are not sent to a server.

Do the calculators show formulas?

Yes. Every calculator shows the formula it uses, the assumptions behind it, and a worked example, so you can reproduce the result yourself.

Which calculators include downloadable Excel workbooks?

Most do — including the mortgage, loan, budget, debt-payoff, profit-margin, and tax tools. Look for the “XLSX” badge on a calculator card, or filter by it above. The workbook is generated from the values you enter.

Why may results differ from banks, tax authorities, or brokers?

They use your exact rate, fees, rounding, eligibility, and current rules — which a general calculator cannot know. Treat results as planning estimates and confirm with official figures.

Are these results financial, tax, legal, business, or medical advice?

No. They are educational estimation tools, not professional advice of any kind, and they do not determine loan approval.

How should I choose the right calculator?

Start from a goal in “Start with what you want to do”, use the search box, or filter by category and feature. Each card shows what the tool does and whether it offers charts, scenarios, or a workbook.

Can I use these calculators outside the United States?

Yes. The tools are currency-neutral — you enter your own rates and amounts and read results in your own currency. Tax and legal rules vary by country, so confirm local rules with a local source.

Can I put these calculators on my own website?

Yes. Most tools on this site can be embedded with a single script tag, and results always match the full calculator page. See website calculator widgets for the snippet and options.

All results are educational and planning estimates only — not financial, tax, legal, business, or medical advice. Verify important decisions with qualified professionals and official sources. See our Methodology, Editorial Policy, Corrections, and Disclaimer.