Calculators
Payment, tax, savings, and everyday math calculators with the formulas shown on each page. Worked examples are in plain HTML so you can check the math before you trust a result.
Quick math and unit conversion tools. 33 tools in this category.
- Password GeneratorGenerate strong, random passwords with customizable length and characters.
- Unit ConverterConvert length, weight, temperature, and volume between common units.
- BMI CalculatorCalculate your Body Mass Index from height and weight in metric or imperial.
- Age CalculatorCalculate your exact age in years, months, and days from your birthdate.
- Days Between DatesCalculate the number of days, weeks, and months between two dates.
- Percentage CalculatorFind percentages, calculate increases/decreases, and solve percent problems.
- Fraction ↔ Decimal ConverterConvert decimals to simplified fractions and fractions to decimals. Supports mixed numbers.
- Tip CalculatorCalculate tip amount and split the bill between multiple people.
- Loan CalculatorCalculate monthly payments, total interest, and amortization for loans.
- Debt Payoff CalculatorPlan payoff for multiple debts with the avalanche method, extra payments, and a fixed or shrinking monthly budget.
- Mortgage CalculatorFree mortgage payment calculator — estimate monthly P&I, total interest, and payments with taxes and insurance.
- Compound Interest CalculatorCalculate compound interest and future value with optional monthly contributions. Free online savings growth tool.
- ROI CalculatorCalculate return on investment (ROI) and annualized ROI from your initial cost and final value or gain.
- Retirement Savings CalculatorProject your retirement nest egg from current savings, monthly contributions, and expected annual return.
- Budget CalculatorBuild a simple monthly budget — track income vs expenses and see how much you have left over.
- Sales Tax CalculatorAdd or remove sales tax from a price. Instantly calculate tax amount and totals for any rate.
- Income Tax EstimatorEstimate U.S. federal income tax from taxable income using current tax brackets. Free rough calculator — not tax advice.
- Currency ConverterConvert between world currencies with a live or manual exchange rate. Fast free FX calculator in your browser.
- Salary to Hourly ConverterConvert annual salary to hourly wage (and back). See monthly, biweekly, weekly, and hourly pay instantly.
- Inflation CalculatorSee how inflation changes purchasing power over time. Compare dollar values between years at any inflation rate.
- Dollar Buying Power CalculatorFind out how much money from one year is worth in another using historical U.S. CPI data — what a dollar was worth then vs now.
- Refinance CalculatorCompare your current loan to a refinance offer — monthly savings, break-even time, and total interest.
- Credit Card Payoff CalculatorEstimate how long to pay off a credit card balance and total interest at your monthly payment and APR.
- Down Payment CalculatorCalculate down payment amount, percent, or affordable home price from the numbers you know.
- Amortization Schedule CalculatorGenerate a full loan amortization schedule with monthly principal, interest, and balance. Download as CSV.
- Net Worth CalculatorAdd up assets and liabilities to calculate your net worth. Free personal balance sheet tool — private in your browser.
- Emergency Fund CalculatorFind your emergency fund target from monthly expenses and months of coverage. Track how much you still need.
- 401(k) Contribution CalculatorEstimate employee and employer 401(k) contributions with match rules, plus optional growth projection.
- APR CalculatorEstimate the true APR of a loan including fees and points — compare stated interest rate vs real cost.
- Discount & Markup CalculatorCalculate sale price after a discount, markup from cost, or selling price from desired profit margin.
- Break-Even CalculatorFind break-even units and revenue from fixed costs, variable cost per unit, and selling price.
- Timezone ConverterConvert a date and time between time zones and check the time around the world.
- Stopwatch & TimerRun a stopwatch with laps or set a countdown timer — all in your browser.