Free Online Calculators
200 calculators across four categories — mortgage and loan math, BMI and calories, school math, and everyday conversions. Every one shows its work, explains the formula, and never asks for an account or sends your numbers anywhere. They all run in your browser, just like our timers.
Financial Calculators(75)
Mortgages, loans, savings, retirement and tax math.
Mortgage CalculatorEstimate your monthly mortgage payment including principal, interest, property tax, insurance and HOA dues.Read the guide →
Loan CalculatorWork out the monthly payment, total interest and payoff cost of any fixed-rate loan.Read the guide →
Auto Loan CalculatorCalculate car payments, total interest and the true cost of a vehicle loan by term.Read the guide →
Personal Loan CalculatorEstimate payments and interest on an unsecured personal loan before you apply.Read the guide →
Business Loan CalculatorProject monthly debt service and total interest on a small business term loan.Read the guide →
Boat Loan CalculatorEstimate monthly payments and interest on a boat or marine loan.Read the guide →
Student Loan CalculatorSee monthly payments, payoff time and lifetime interest on student loan debt.Read the guide →
Repayment CalculatorFind the monthly repayment amount for any borrowed sum over a fixed term.Read the guide →
Lease CalculatorEstimate a level lease payment from the financed amount, rate and term.Read the guide →
Auto Lease CalculatorEstimate a car lease payment from the amount you are financing over the lease term.Read the guide →
Refinance CalculatorCompare a new loan payment against your current one to see if refinancing pays off.Read the guide →
Amortization CalculatorSee how each payment splits between principal and interest, and what your balance is after any year.Read the guide →
Mortgage Payoff CalculatorSee how much time and interest an extra monthly payment shaves off your mortgage.Read the guide →
Interest CalculatorCalculate how much interest a deposit earns over time with regular contributions.Read the guide →
Compound Interest CalculatorSee how compounding frequency and time change the final value of an investment.Read the guide →
Simple Interest CalculatorCalculate simple (non-compounding) interest on a loan or deposit.Read the guide →
Payment CalculatorFind the monthly payment for a loan, or the term needed to hit a target payment.Read the guide →
Retirement CalculatorProject your retirement nest egg and the annual income it can safely support.Read the guide →
401(k) CalculatorProject your 401(k) balance including the employer match on your contributions.Read the guide →
Roth IRA CalculatorSee what a Roth IRA could be worth, with every dollar of growth tax-free at withdrawal.Read the guide →
RMD CalculatorEstimate your required minimum distribution from a retirement account by age.Read the guide →
Pension CalculatorEstimate an annual pension benefit from years of service and final average salary.Read the guide →
Social Security CalculatorCompare Social Security benefits for claiming early, at full retirement age, or at 70.Read the guide →
Annuity Payout CalculatorSee how much income a lump sum can pay out per month for a set number of years.Read the guide →
Investment CalculatorProject investment growth from a starting balance plus regular contributions.Read the guide →
Average Return CalculatorCalculate the average annual return (CAGR) between a starting and ending value.Read the guide →
ROI CalculatorCalculate return on investment as a percentage and as an annualized figure.Read the guide →
IRR CalculatorFind the internal rate of return for an initial outlay and a stream of yearly cash flows.Read the guide →
Present Value CalculatorFind what a future sum of money is worth in today's dollars.Read the guide →
Future Value CalculatorFind what today's money will be worth at a given rate in the future.Read the guide →
Inflation CalculatorSee how inflation changes the buying power of an amount of money over time.Read the guide →
Savings CalculatorWork out how long it takes to reach a savings goal, or what to save each month.Read the guide →
CD CalculatorCalculate the maturity value and interest earned on a certificate of deposit.Read the guide →
Bond CalculatorPrice a bond and see its current yield from coupon, face value and market rate.Read the guide →
Mutual Fund CalculatorSee how an expense ratio eats into mutual fund returns over the long run.Read the guide →
Credit Card CalculatorSee how long a credit card balance takes to clear at your current payment.Read the guide →
Credit Cards Payoff CalculatorFind the monthly payment needed to clear a credit card balance by a target date.Read the guide →
Debt Payoff CalculatorEstimate how long your total debt takes to clear and what the interest costs.Read the guide →
Debt Consolidation CalculatorCompare your current debt payments against a single consolidated loan.Read the guide →
Debt-to-Income Ratio CalculatorCalculate the DTI ratio lenders use to decide whether you qualify for a mortgage.Read the guide →
House Affordability CalculatorFind the home price you can realistically afford based on income, debts and down payment.Read the guide →
Down Payment CalculatorCalculate the down payment for any home price and see the loan amount that remains.Read the guide →
FHA Loan CalculatorEstimate an FHA mortgage payment including the mortgage insurance premium.Read the guide →
VA Mortgage CalculatorEstimate a VA loan payment including the VA funding fee, with no down payment required.Read the guide →
Home Equity Loan CalculatorSee how much equity you can borrow and what the fixed monthly payment would be.Read the guide →
HELOC CalculatorEstimate interest-only HELOC payments during the draw period and the repayment after it.Read the guide →
Rent CalculatorFind the rent you can comfortably afford based on your income and the 30% rule.Read the guide →
Rent vs. Buy CalculatorCompare the monthly cost of renting against owning the same home.Read the guide →
Real Estate CalculatorAnalyze a property's cap rate, cash flow and cash-on-cash return.Read the guide →
Rental Property CalculatorModel rental income, vacancy, expenses and cash flow on an investment property.Read the guide →
Income Tax CalculatorEstimate federal income tax, effective rate and take-home pay from your gross income.Read the guide →
Take-Home Paycheck CalculatorEstimate net pay per paycheck after federal tax, FICA, state tax and deductions.Read the guide →
Salary CalculatorConvert between hourly, weekly, monthly and annual pay in one step.Read the guide →
Marriage Tax CalculatorSee whether filing jointly creates a marriage bonus or a marriage penalty.Read the guide →
Estate Tax CalculatorEstimate federal estate tax exposure against the lifetime exemption.Read the guide →
Discount CalculatorFind the sale price and the amount saved from any percentage discount.Read the guide →
Percent Off CalculatorQuickly work out what a percent-off deal costs and how much you save.Read the guide →
Commission CalculatorCalculate sales commission from a sale amount and rate, with optional base pay.Read the guide →
Margin CalculatorCalculate gross margin, markup and profit from cost and selling price.Read the guide →
Interest Rate CalculatorWork backwards from a known payment to find the interest rate on a loan.Read the guide →
Cash Back or Low Interest CalculatorDecide whether a dealer rebate or a promotional finance rate saves you more.Read the guide →
Depreciation CalculatorCalculate straight-line and declining-balance depreciation on an asset.Read the guide →
Payback Period CalculatorFind how long an investment takes to repay its initial cost.Read the guide →
College Cost CalculatorProject the total future cost of college and what you need to save monthly.Read the guide →
Currency CalculatorConvert between currencies using an exchange rate you enter, with fee impact shown.Read the guide →
Finance CalculatorSolve the classic time-value-of-money relationship between PV, FV, rate and time.Read the guide →
Mortgage Calculator UKEstimate UK mortgage repayments, including interest-only comparison and stamp duty.Read the guide →
Fitness & Health Calculators(34)
BMI, calories, macros, pregnancy and training numbers.
BMI CalculatorCalculate body mass index from height and weight, with the standard weight category.Read the guide →
BMR CalculatorFind your basal metabolic rate — the calories your body burns at complete rest.Read the guide →
TDEE CalculatorCalculate total daily energy expenditure — the calories you burn in a full day.Read the guide →
Calorie CalculatorFind your daily calorie target for losing, maintaining or gaining weight.Read the guide →
Protein CalculatorFind your daily protein target based on body weight and training goal.Read the guide →
Carbohydrate CalculatorWork out daily carbohydrate grams from your calorie target and diet style.Read the guide →
Fat Intake CalculatorCalculate daily fat grams and the minimum needed for hormone health.Read the guide →
Body Fat CalculatorEstimate body fat percentage using the U.S. Navy tape measurement method.Read the guide →
Army Body Fat CalculatorCheck body fat against U.S. Army standards using the tape test.Read the guide →
Ideal Weight CalculatorCompare ideal body weight estimates from four established clinical formulas.Read the guide →
Healthy Weight CalculatorFind the healthy weight range for your height using standard BMI bands.Read the guide →
Overweight CalculatorSee how far your current weight is from the healthy BMI range for your height.Read the guide →
Anorexic BMI CalculatorCheck BMI against clinical underweight thresholds used in eating disorder screening.Read the guide →
Calories Burned CalculatorEstimate calories burned during exercise using MET values and body weight.Read the guide →
One Rep Max CalculatorEstimate your one-rep max from a set at a lighter weight, plus training percentages.Read the guide →
Target Heart Rate CalculatorFind your training heart rate zones from age and resting heart rate.Read the guide →
Pace CalculatorConvert between race pace, distance and finish time for running, walking or cycling.Read the guide →
Pregnancy CalculatorTrack pregnancy week by week and see the estimated due date from your last period.Read the guide →
Due Date CalculatorEstimate your baby's due date from the first day of your last period.Read the guide →
Pregnancy Conception CalculatorEstimate the conception date window from a due date or last period.Read the guide →
Ovulation CalculatorPredict your ovulation date and fertile days for the next few cycles.Read the guide →
Period CalculatorPredict your next several period start dates from your cycle length.Read the guide →
Pregnancy Weight Gain CalculatorSee the recommended pregnancy weight gain range based on pre-pregnancy BMI.Read the guide →
GFR CalculatorEstimate glomerular filtration rate to gauge kidney function from serum creatinine.Read the guide →
Body Surface Area CalculatorCalculate body surface area, used clinically for drug and fluid dosing.Read the guide →
BAC CalculatorEstimate blood alcohol content from drinks, body weight and time elapsed.Read the guide →
Weight Watcher Points CalculatorEstimate points for a food from calories, saturated fat, sugar and protein.Read the guide →
Sleep CalculatorFind the best bedtimes or wake times based on 90-minute sleep cycles.Read the guide →
Math Calculators(41)
Percentages, geometry, statistics and conversions for students.
Percentage CalculatorFind a percentage of a number, a percent change, or what percent one number is of another.Read the guide →
Fraction CalculatorAdd, subtract, multiply and divide two fractions and see the simplified result.Read the guide →
Mean, Median, Mode, Range CalculatorGet all four measures of central tendency and spread from one list of numbers.Read the guide →
Standard Deviation CalculatorCalculate population and sample standard deviation, variance and mean.Read the guide →
Statistics CalculatorFull descriptive statistics for a dataset: mean, median, quartiles, deviation and more.Read the guide →
Z-score CalculatorConvert a raw value into a z-score and read off the probability below it.Read the guide →
Sample Size CalculatorFind how many responses a survey needs for a given margin of error.Read the guide →
Permutation and Combination CalculatorCalculate permutations (order matters) and combinations (order does not).Read the guide →
Exponent CalculatorRaise any number to any power, including fractional and negative exponents.Read the guide →
Quadratic Formula CalculatorSolve any quadratic equation and see the discriminant and vertex.Read the guide →
Slope CalculatorFind slope, distance, midpoint and the line equation from two points.Read the guide →
Distance CalculatorFind the straight-line distance between two points in two or three dimensions.Read the guide →
Pythagorean Theorem CalculatorFind the missing side of a right triangle from the other two.Read the guide →
Right Triangle CalculatorSolve a right triangle for sides, angles, area and perimeter.Read the guide →
Triangle CalculatorFind area, perimeter and angles of any triangle from its three sides.Read the guide →
Circle CalculatorCalculate area, circumference and diameter of a circle from its radius.Read the guide →
Area CalculatorFind the area of rectangles, circles, triangles, trapezoids and ellipses.Read the guide →
Surface Area CalculatorCalculate the surface area of a box, sphere, cylinder or cone.Read the guide →
Volume CalculatorCalculate the volume of boxes, cylinders, spheres, cones and pyramids.Read the guide →
Percent Error CalculatorCompare an experimental value to the accepted value as a percentage.Read the guide →
Rounding CalculatorRound a number to decimals, whole numbers, tens, hundreds or significant figures.Read the guide →
Scientific Notation CalculatorConvert numbers to and from scientific notation and engineering notation.Read the guide →
Half-Life CalculatorCalculate remaining quantity after radioactive or exponential decay.Read the guide →
Number Sequence CalculatorFind terms and sums of arithmetic and geometric sequences.Read the guide →
Prime Factorization CalculatorBreak any number into its prime factors and list all its divisors.Read the guide →
Greatest Common Factor CalculatorFind the greatest common factor of two or more numbers.Read the guide →
Least Common Multiple CalculatorFind the least common multiple of two or more numbers.Read the guide →
Long Division CalculatorDivide two numbers and see the quotient, remainder and decimal result.Read the guide →
Everyday Calculators(50)
Dates, hours, units, weather and handy converters.
Age CalculatorCalculate your exact age in years, months, days — plus total days and your next birthday.Read the guide →
Time Duration CalculatorFind the exact duration between two times, even across midnight.Read the guide →
Hours CalculatorAdd up worked hours from start and end times with break time subtracted.Read the guide →
Time Card CalculatorTurn in/out times into total weekly hours and an overtime split.Read the guide →
GPA CalculatorCalculate your grade point average from letter grades and credit hours.Read the guide →
Grade CalculatorFind the score you need on the final exam to reach your target course grade.Read the guide →
Height CalculatorConvert between feet/inches and centimeters and estimate a child's adult height.Read the guide →
Tip CalculatorCalculate the tip and split the bill evenly between any number of people.Read the guide →
Fuel Cost CalculatorEstimate the fuel cost of a trip from distance, MPG and the price per gallon.Read the guide →
Conversion CalculatorConvert length, weight, volume and temperature between metric and U.S. units.Read the guide →
Weight CalculatorConvert weight between pounds, kilograms, stones, ounces and grams.Read the guide →
Square Footage CalculatorCalculate the square footage of a room, plus cost per square foot.Read the guide →
Concrete CalculatorEstimate concrete needed for a slab in cubic yards and number of bags.Read the guide →
Gravel CalculatorEstimate gravel needed for driveways and paths in cubic yards and tons.Read the guide →
Tile CalculatorWork out how many tiles you need for a floor or wall, including waste.Read the guide →
Voltage Drop CalculatorCheck voltage drop over a wire run and see if your gauge is adequate.Read the guide →
Ohm's Law CalculatorSolve voltage, current, resistance and power from any two knowns.Read the guide →
Resistor CalculatorCombine resistors in series and parallel, and find the series resistor for an LED.Read the guide →
Electricity CalculatorFind the energy an appliance uses per day and its monthly cost.Read the guide →
Horsepower CalculatorConvert between horsepower, kilowatts and torque-based horsepower.Read the guide →
Engine Horsepower CalculatorEstimate engine horsepower from quarter-mile trap speed and vehicle weight.Read the guide →
Tire Size CalculatorDecode a tire size and compare diameter, circumference and speedometer error.Read the guide →
Wind Chill CalculatorCalculate the wind chill temperature using the official NWS formula.Read the guide →
Bandwidth CalculatorFind download time for a file, or the bandwidth a transfer requires.Read the guide →
IP Subnet CalculatorCalculate network address, broadcast, usable host range and mask for a CIDR block.Read the guide →
Password GeneratorGenerate strong random passwords and check how long brute force would take.Read the guide →
Day of the Week CalculatorFind the day of the week any date falls on, past or future.Read the guide →
Shoe Size Conversion CalculatorConvert shoe sizes between US, UK and EU sizing for men and women.Read the guide →
Molarity CalculatorCalculate solution molarity from moles of solute and liters of solution.Read the guide →
Molecular Weight CalculatorSum atomic weights of a simple formula to get molecular mass.Read the guide →
Why build calculators on a timer site?
TimerHubs started as a coaching stopwatch, but every one of these calculators exists for the same reason: quick, honest math without a login wall. Like our stopwatch and Pomodoro timer, each calculator runs entirely in your browser — your salary, your measurements and your health numbers never leave your device.
Disclaimer: these calculators are for general information and education. Health results are estimates, not medical advice, and financial results are illustrations, not tax, legal or investment advice. Always confirm decisions with a qualified professional.