Free Online Calculators
Fast, accurate, and easy-to-use calculators for everyday math. No sign-up required.
Finance Calculators
Mortgage Calculator
Estimate your monthly mortgage payment, total cost, and total interest paid over the life of the loan.
Compound Interest Calculator
See how your money grows over time with compound interest. Adjust rate, frequency, and duration.
Percentage Calculator
Find percentages, calculate percent change, or determine what percentage one number is of another.
Loan Amortization Calculator
See your complete loan repayment schedule — monthly payment, principal vs. interest breakdown, and payoff timeline.
Auto Loan Calculator
Calculate your monthly car payment. Factor in down payment, trade-in value, interest rate, and loan term.
Credit Card Payoff Calculator
Find out how long it takes to pay off your credit card balance and how much interest you will pay in total.
Tip Calculator
Quickly calculate the tip amount, total bill, and per-person split for any restaurant or service bill.
Split Bill Calculator
Divide any bill evenly among a group. Optionally add a tip and see exactly what each person owes.
Paycheck Calculator
Estimate your take-home pay after federal income tax, FICA, and state taxes for any pay period.
Savings Goal Calculator
Find out how long it takes to reach a savings goal given your current balance, monthly contributions, and interest rate.
Budget Calculator
Plan your monthly budget by entering your income and expense categories to see your remaining balance and savings rate.
Debt-to-Income Calculator
Calculate your debt-to-income ratio and see how lenders evaluate your ability to manage monthly payments.
Break-Even Calculator
Determine the break-even point for a product or business given fixed costs, variable costs, and selling price.
Health & Fitness Calculators
BMI Calculator
Calculate your Body Mass Index. Supports metric and imperial units with instant category feedback.
BMR Calculator
Calculate your Basal Metabolic Rate — the calories your body burns at rest — using the Mifflin-St Jeor equation.
TDEE Calculator
Find your Total Daily Energy Expenditure based on your BMR and activity level to set accurate calorie goals.
Body Fat Calculator
Estimate your body fat percentage using the US Navy Method with height, waist, neck, and hip measurements.
Ideal Body Weight Calculator
Find your ideal weight range using the Devine and Hamwi formulas based on height and sex.
Calorie Deficit Calculator
Calculate your daily calorie deficit or surplus and see how fast you will lose or gain weight.
Macro Calculator
Break down your daily calorie goal into protein, carbs, and fat grams based on your fitness objective.
Water Intake Calculator
Find your recommended daily water intake in liters, ounces, and cups based on weight and activity level.
One-Rep Max Calculator
Estimate your 1RM for any lift using the Epley and Brzycki formulas, plus a full percentage training table.
Running Pace Calculator
Calculate your running pace per km and per mile from any distance and finish time.
Waist-to-Hip Ratio Calculator
Measure your waist-to-hip ratio and see how it correlates to cardiovascular health risk by sex.
Ovulation Calculator
Calculate your ovulation date and 6-day fertile window from your last period and cycle length.
BAC Calculator
Estimate your blood alcohol content (BAC) using the Widmark formula — and how long until you are sober.
Calories Burned Calculator
Calculate calories burned during any exercise or activity based on MET values, weight, and duration.
Pregnancy Weight Gain Calculator
See your recommended pregnancy weight gain range based on IOM guidelines and your pre-pregnancy BMI.
Due Date from Conception
Calculate your estimated due date from your conception date and see your current gestational age.
Date & Time Calculators
Age Calculator
Calculate your exact age in years, months, and days from your birthdate.
Days Between Dates
Find the exact number of days, weeks, and months between any two dates.
Business Days Calculator
Count the number of working days between two dates, excluding weekends.
Time Duration Calculator
Calculate elapsed time between two times of day, with optional break deduction.
Day of the Week Calculator
Find out what day of the week any past or future date falls on.
Countdown Calculator
Count down the days, hours, minutes, and seconds to any future date.
Leap Year Calculator
Check if any year is a leap year and find the next and previous leap years.
Work Hours Calculator
Track total hours worked across multiple shifts with break time deductions.
Time Zone Converter
Convert any date and time between two time zones using standard IANA names.
Add/Subtract Days Calculator
Add or subtract any number of days from a date to find the resulting date.
How Many Days Until
Count down the exact days, weeks, and hours until any future date — holidays, birthdays, events.
Unit Conversions Calculators
Length Converter
Convert between millimetres, centimetres, metres, kilometres, inches, feet, yards, miles, and nautical miles.
Weight Converter
Convert between milligrams, grams, kilograms, tonnes, ounces, pounds, stone, and US/UK tons.
Temperature Converter
Convert temperatures between Celsius, Fahrenheit, Kelvin, and Rankine instantly.
Speed Converter
Convert between metres per second, kilometres per hour, miles per hour, knots, and feet per second.
Cooking Measurements Converter
Convert cooking measurements between teaspoons, tablespoons, cups, fluid ounces, pints, quarts, gallons, and millilitres.
Fuel Efficiency Converter
Convert fuel economy between MPG (US), MPG (UK), litres per 100 km, and kilometres per litre.
Pressure Converter
Convert between Pascals, kilopascals, bar, PSI, atmospheres, mmHg, and inHg.
Energy Converter
Convert between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, BTUs, and foot-pounds.
Shoe Size Converter
Convert shoe sizes between US Men, US Women, UK, EU, and foot length in centimetres.
Roman Numeral Converter
Convert any number (1–3999) to Roman numerals, or convert a Roman numeral back to an integer.
Home & Construction Calculators
Square Footage Calculator
Calculate area in square feet, square meters, and square yards. Supports feet, meters, yards, inches, and centimeters.
Paint Calculator
Calculate how many gallons of paint you need for a room based on wall area, coats, and coverage rate.
Flooring Calculator
Calculate the square footage of flooring or tile needed for a room, including a waste factor for cuts.
Concrete Calculator
Calculate cubic yards of concrete needed for a slab or cylindrical pour, plus the number of bags required.
Fence Calculator
Estimate the posts, rails, and pickets needed for a fence based on total length and post spacing.
Mulch & Soil Calculator
Calculate cubic yards of mulch, soil, or gravel needed for a garden bed based on area and desired depth.
Roofing Calculator
Calculate roofing squares and shingle bundles needed based on roof footprint, pitch, and waste factor.
Carpet Calculator
Calculate how many square yards of carpet you need for a room, with a waste percentage for seams and cuts.
Deck Calculator
Estimate the number of deck boards and total linear feet of lumber needed for a rectangular deck.
Moving Truck Size Calculator
Find the right rental truck size for your move based on the number of bedrooms and furniture load.
Wallpaper Calculator
Calculate how many rolls of wallpaper you need for a room, accounting for doors, windows, and pattern repeat.
Math & Science Calculators
Area Calculator
Calculate the area of circles, rectangles, triangles, trapezoids, ellipses, and sectors.
Volume Calculator
Calculate the volume of cubes, rectangular prisms, cylinders, spheres, cones, and pyramids.
Perimeter Calculator
Calculate the perimeter or circumference of squares, rectangles, triangles, circles, and regular polygons.
Pythagorean Theorem Calculator
Find any side of a right triangle given the other two using the Pythagorean theorem (a² + b² = c²).
Quadratic Formula Calculator
Solve any quadratic equation ax² + bx + c = 0. Returns real and complex roots with the discriminant.
GCF & LCM Calculator
Find the Greatest Common Factor and Least Common Multiple of two numbers with step-by-step working.
Standard Deviation Calculator
Calculate mean, standard deviation, variance, min, max, and range for any set of numbers.
Probability Calculator
Calculate P(A and B), P(A or B), and conditional probabilities for independent and dependent events.
Kinetic Energy Calculator
Calculate kinetic energy (KE = ½mv²) in joules, kilojoules, and foot-pounds. Supports kg, lb, m/s, mph.
Free Fall Calculator
Calculate free fall time, distance, and final velocity given height or time. Metric and imperial units.
Percentage Change Calculator
Calculate the percentage increase or decrease between two values instantly.
Ratio Calculator
Simplify ratios, solve for missing values, and compare proportions.
Scientific Notation Converter
Convert numbers between standard form and scientific notation instantly.
Fraction to Decimal Converter
Convert fractions to decimals, percentages, and simplified form instantly.
Significant Figures Calculator
Round any number to a specified count of significant figures.
Automotive Calculators
Fuel Cost Calculator
Calculate total fuel cost for any trip. Supports MPG/imperial and L/100km/metric.
Gas Mileage Calculator
Calculate MPG or L/100km from distance and fuel used.
Road Trip Cost Calculator
Estimate total road trip cost including fuel, food, and lodging.
Car Depreciation Calculator
See how your car loses value year by year with a depreciation schedule.
EV Range & Charging Cost Calculator
Estimate electric vehicle range and charging cost from battery size and efficiency.
Tire Size Calculator
Compare two tire sizes — diameter, circumference, and speedometer error.
Horsepower & Torque Calculator
Convert between horsepower, torque (ft·lb / Nm), and RPM using HP = Torque × RPM / 5252.
Oil Change Cost Calculator
Calculate annual and lifetime oil change costs based on mileage and service interval.
Towing Capacity Calculator
Check if your vehicle can safely tow a trailer and calculate tongue weight.
Car Lease vs Buy Calculator
Compare total lease cost vs buying — monthly payments, equity, and net cost.
EV vs. Gas Calculator
Compare the total 5-year cost of owning an EV vs. a gas vehicle including fuel, insurance, and maintenance.
Advanced Finance Calculators
Retirement Calculator
Project your 401k or retirement account balance with contributions, employer match, and compound growth.
Roth vs Traditional IRA Calculator
Compare Roth vs Traditional IRA after-tax values based on current and expected future tax rates.
Investment ROI Calculator
Calculate total return, percentage gain, and annualized (CAGR) return on any investment.
Dividend Yield Calculator
Calculate dividend yield %, yield on cost, and annual/monthly/quarterly dividend income.
Net Worth Calculator
Calculate your total net worth by entering assets and liabilities across all categories.
Inflation Calculator
Calculate the future value of money or how much past amounts are worth in today's dollars.
Rent vs Buy Calculator
Compare total cost of renting vs buying a home over any time period, including equity and appreciation.
Emergency Fund Calculator
Calculate your recommended 3- and 6-month emergency fund target and how long to reach it.
College Savings Calculator
Estimate total college costs and monthly savings needed to fund a 529 plan for your child.
Tax Bracket Calculator
Estimate 2025 federal income tax by bracket. Shows effective rate, marginal rate, and after-tax income.
Dollar Cost Averaging Calculator
See how regular fixed investments grow over time with dollar cost averaging. Model your DCA strategy.
FIRE Number Calculator
Calculate your FIRE number — the portfolio size needed to retire early based on the 4% safe withdrawal rule.
Life Insurance Needs Calculator
Estimate how much life insurance coverage you need based on income, debts, dependents, and existing assets.
Education & Life Calculators
GPA Calculator
Calculate your weighted GPA using letter grades and credit hours for any number of courses.
Grade Needed Calculator
Find out what grade you need on remaining assignments to hit your target course grade.
Test Score Calculator
Convert a raw test score to a percentage and letter grade instantly.
Freelance Rate Calculator
Calculate the minimum hourly freelance rate to hit your income goals after taxes and expenses.
Hourly to Salary Calculator
Convert an hourly wage to annual salary, monthly, biweekly, and daily pay equivalents.
Cost Per Use Calculator
Calculate cost per use of any item to determine its true value vs. a cheaper alternative.
Wedding Budget Calculator
Break down your wedding budget by category — venue, photography, catering, flowers, and more.
Vacation Cost Calculator
Estimate total vacation costs including flights, hotel, food, and activities for any trip.
Pregnancy Due Date Calculator
Calculate your estimated due date from your last menstrual period and see trimester milestones.
Sleep Cycle Calculator
Find the best bedtime based on your wake time to align with natural 90-minute sleep cycles.
Pet Cost Calculator
Estimate the first-year and ongoing annual cost of owning a dog or cat including food, vet care, and supplies.
Carbon Footprint Calculator
Estimate your annual carbon footprint from home energy, driving, flights, and diet. See where you can reduce.
Taxes Calculators
Sales Tax Calculator
Calculate sales tax on any purchase. Enter a price and tax rate to see tax amount and total price — or reverse-calculate from a tax-inclusive total.
Capital Gains Tax Calculator
Estimate federal capital gains tax on stocks, real estate, or other assets. Handles short-term vs long-term rates and the 3.8% NIIT.
Lottery Tax Calculator
See how much of a lottery jackpot you keep after federal and state taxes — lump sum or annuity.
Property Tax Calculator
Estimate annual property taxes and monthly escrow payments based on home value and local tax rate.
Self-Employment Tax Calculator
Calculate self-employment (SE) tax, income tax, and quarterly estimated payments for freelancers and contractors.
Business Calculators
Profit Margin Calculator
Calculate gross profit margin, net margin, and markup percentage from revenue and cost.
Markup Calculator
Find selling price, profit, and margin from cost and markup percentage.
Break-Even Units Calculator
Calculate how many units you need to sell to cover fixed and variable costs.
Employee Cost Calculator
Estimate the true total annual cost of hiring an employee including taxes and benefits.
Invoice Calculator
Calculate invoice totals with hours, expenses, and tax to generate billable amounts.
Real Estate Calculators
How Much House Can I Afford
Find your maximum home purchase price based on income, debts, and down payment using the 28/36 rule.
Refinance Calculator
Should you refinance? Calculate new monthly payment, monthly savings, and the break-even point on closing costs.
Rental Property Calculator
Analyze a rental property investment — NOI, cap rate, monthly cash flow, and cash-on-cash return.
Closing Cost Calculator
Estimate buyer closing costs for a home purchase or refinance, with a full line-item breakdown.
Home Equity & HELOC Calculator
Calculate your current home equity, LTV ratio, and maximum HELOC borrowing limit.
Fun & Viral Calculators
Dog Age Calculator
Convert your dog's age to human years using a size-adjusted formula — not the old 7× myth.
Cat Age Calculator
Convert your cat's age to human years and find out their life stage — kitten to geriatric.
Age on Other Planets
Find out how old you would be on Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune.
Life in Numbers
See your life expressed in heartbeats, breaths, hours slept, steps walked, and more based on your age.
How Rich Am I?
Compare your annual income to your country and the global population to see your wealth percentile rank.
Smoking Cost Calculator
Calculate how much money and how many years of life you have spent — or will spend — on cigarettes.
Coffee Cost Calculator
Calculate your lifetime coffee spend and daily caffeine intake from your daily coffee habit.
Alcohol Calorie Calculator
Count the calories in your weekly drinks — beer, wine, and spirits — and see the annual total.
Milestone Age Calculator
Find out when you will hit 1 million hours, days, minutes, or seconds old based on your birthday.
Retirement Countdown
See exactly how many days, hours, and minutes remain until your target retirement age.
Birthday Countdown
Count down the exact days, hours, and minutes until your next birthday and see how old you will be.
Lottery Odds Calculator
See how unlikely it is to win the lottery compared to being struck by lightning or other rare events.
Reading Time Calculator
Calculate how long it will take to read any book based on page count and your reading speed.
Typing Speed Calculator
Find out how many pages, words, or books you could type in an hour, day, or year at your WPM.