Everyday math, done plainly.
Free calculators for mortgages, paychecks, taxes, savings, tips, health, and dates. Type your numbers and see the answer instantly. Nothing you enter leaves your browser.
MoneyMortgages, loans, savings, pay
Mortgage CalculatorMonthly payment with tax, insurance, PMILoan CalculatorAuto or personal loan paymentsCompound Interest CalculatorWatch savings grow over timeCredit Card Payoff CalculatorMonths to debt-free and interestRetirement Savings Calculator401(k) growth with employer matchHourly to Salary CalculatorHourly wage ↔ yearly salaryAuto Loan CalculatorCar payment with trade-in and taxHome Affordability CalculatorHow much house you can affordDebt Payoff CalculatorSnowball vs. avalanche plan
Taxes & PayTake-home pay, refunds, 1099 tax
Paycheck CalculatorTake-home pay after taxes, by stateIncome Tax & Refund CalculatorWill you get a refund or owe?Self-Employment Tax Calculator1099 tax and quarterly estimatesOvertime Pay CalculatorOvertime pay and the new deductionNo Tax on Tips CalculatorThe new tip income deductionRoth vs. Traditional CalculatorWhich retirement account wins
EverydayTips, tax, discounts, dates
Sales Tax CalculatorAdd or back out sales taxTip CalculatorTip and split the billPercentage CalculatorPercent of, percent changeDiscount CalculatorSale price after % offUnit Converterlb↔kg, °F↔°C, ft↔mGas Cost CalculatorTrip fuel cost from MPGGPA CalculatorSemester and cumulative GPAFinal Grade CalculatorScore you need on the finalSquare Footage & Concrete CalculatorArea, flooring, and concrete
Health & TimeBMI, calories, dates, hours
Age CalculatorExact age and next birthdayDate CalculatorDays between dates, add daysHours Worked CalculatorWeekly time card and payBMI CalculatorBody mass index and healthy rangeCalorie CalculatorDaily calories to maintain weightPregnancy Due Date CalculatorDue date, week, trimesterOvulation CalculatorFertile window and ovulation dateMacro CalculatorProtein, carbs, and fat per dayDog Age CalculatorDog years to human years
Why Plainsum?
Every calculator shows how the answer was worked out, explains the formula in plain English, and runs entirely on your device. There are no sign-ups and no stored data.
Tax calculators use 2026 IRS figures and current state rates, and every page lists its sources and the date it was last reviewed. See how we calculate.