Foundation directory
Essential Calculators & Time Tools
Everyday math
- Basic CalculatorFormulaThe named inputs are substituted into the visible formula to produce the result.
- Scientific CalculatorFormulaThe named inputs are substituted into the visible formula to produce the result.
- Percentage CalculatorFormulaPercentage, base number, part, whole, original and new values define the percent record.
- Fraction CalculatorFormulaa, b, c and d are the compared quantities in equivalent ratios.
- Percentage Change CalculatorFormulaOriginal value and new value define the baseline and direction of change.
- Percent Error CalculatorFormulaMeasured and true values define the absolute relative error.
Buying a home
- Mortgage CalculatorFormulaHome price, down payment, annual rate, term and monthly housing costs define the mortgage scenario.
- Mortgage Repayment CalculatorFormulaPrincipal, interest rate, repayment term and optional extra payment define the repayment schedule.
- Mortgage Payoff CalculatorFormulaCurrent balance, rate, scheduled payment and extra principal define the payoff projection.
- Mortgage Amortization CalculatorFormulaLoan balance, rate, payment frequency, term and start date define the amortization table.
- Loan CalculatorFormulaLoan amount, interest rate, term, fees and payment timing define the borrowing cost.
- Personal Loan CalculatorFormulaBorrowed amount, APR, term and fees define the personal-loan payment estimate.
Health
- BMI CalculatorFormulaWeight is measured in kilograms and height is measured in metres.
- Calorie CalculatorFormulaBMR, activity level and goal adjustment determine estimated daily calories.
- Body Fat CalculatorFormulaBody measurements are used as inputs to an estimated body-fat model.
- BMR CalculatorFormulaw is weight in kilograms, h is height in centimetres and a is age in years.
- TDEE CalculatorFormulaBMR is multiplied by the selected activity factor.
- Macro CalculatorFormulaProtein, carbohydrate and fat grams are converted to calories using standard energy factors.
Dates and deadlines
- Age CalculatorFormulaBirth date and target date define the calendar span.
- Date Duration CalculatorFormulaStart and end dates or times define the signed elapsed duration.
- Date Add or Subtract CalculatorFormulaStart date, target date and counting rules determine the returned calendar result.
- Time Duration CalculatorFormulaStart and end dates or times define the signed elapsed duration.
- Time Add or Subtract CalculatorFormulaStart date, target date and counting rules determine the returned calendar result.
- Business Days CalculatorFormulaStart date, target date and counting rules determine the returned calendar result.
Moon and night sky
- Sunrise and Sunset CalculatorFormulaObserver location, date and solar geometry determine the sky event time.
- Moonrise and Moonset CalculatorFormulaDate, observer location and Sun/Moon/planet geometry define the sky state.
- Moon Phase CalculatorFormulaDate, observer location and Sun/Moon/planet geometry define the sky state.
- Day Length CalculatorFormulaObserver location, date and solar geometry determine the sky event time.
- Seasons and Solstices CalculatorFormulaObserver location, date and solar geometry determine the sky event time.
- Eclipse CalculatorFormulaDate, observer location and Sun/Moon/planet geometry define the sky state.
