CalcEmperor

Calculators that show their math

Free, quick and private. Every result comes with the formula behind it, so you can check the answer instead of trusting it.

Loans & debt

Loan CalculatorMonthly payment, total interest and a year-by-year balance for any fixed-rate loan.Mortgage CalculatorFull monthly housing payment with property tax, insurance, PMI and HOA.Auto Loan CalculatorCar payment with down payment, trade-in, sales tax and fees.Credit Card Payoff CalculatorHow long it takes to clear a balance and how much interest you will pay.

Savings & income

Compound Interest CalculatorProject savings or investment growth with monthly contributions.Savings Goal CalculatorHow much to save each month to reach a target amount by a set date.Retirement CalculatorProject your retirement savings, in future and in today's dollars.Hourly to Salary CalculatorConvert hourly pay to annual, monthly, weekly and biweekly pay, and back.50/30/20 Budget CalculatorSplit your after-tax income into needs, wants and savings.

Everyday math

Profit Margin CalculatorMargin, markup and profit from cost and price, plus the price for a target margin.Percentage CalculatorPercent of a number, what percent one number is of another, and percent change.Tip CalculatorWork out the tip and split the bill between any number of people.Sales Tax CalculatorAdd sales tax to a price, or remove it from a total. Works for VAT and GST too.Discount CalculatorSale price and savings after a percentage discount, including stacked discounts.

Date & time

Age CalculatorExact age in years, months and days, plus your next birthday.Days Between Dates CalculatorCount the days, weeks, months and weekdays between two dates.Add or Subtract Days from a DateFind the date that is a number of days, weeks, months or years from any date.

Health

BMI CalculatorBody mass index in metric or imperial units, with the healthy weight range for your height.Calorie Calculator (BMR & TDEE)Estimate the calories you burn each day at rest and with activity.

Unit converters

Length ConverterConvert mm, cm, m, km, inches, feet, yards and miles.Weight ConverterConvert kg, grams, pounds, ounces, stone and tonnes.Temperature ConverterConvert Celsius, Fahrenheit and Kelvin with formulas and a reference chart.

Text & security

Word CounterLive word, character, sentence and paragraph count with reading time.Password GeneratorCreate strong random passwords in your browser. Nothing is sent or stored.

Guides

How to calculate a monthly loan paymentThe formula, a full worked example, and the spreadsheet shortcut.How compound interest worksWhy interest on interest is so powerful, with clear examples.How to calculate percentage changeThe formula for percent increase and decrease, plus the mistakes to avoid.How much house can I afford? The 28/36 ruleA simple income-based method for setting a home budget.How to pay off credit card debt fasterAvalanche versus snowball, with real numbers and a step-by-step plan.How much car can I afford? The 20/4/10 ruleA simple rule for keeping car costs in proportion to your income.The 4% rule: how much do you need to retire?What the 4% rule says, how to use it, and its limits.The 50/30/20 budget rule explainedA simple way to split your income between needs, wants and savings.Profit margin vs markup: what's the difference?Why margin and markup differ, and how to price for the profit you want.BMR and TDEE explainedWhat BMR and TDEE mean and how to use your calorie estimate sensibly.

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Everything on CalcEmperor runs in your browser, so the numbers you type stay on your device. Each tool page includes the formula, a worked example and answers to common questions. Results are estimates for planning and education, not professional advice.