All Calculators
Finance (14 calculators)
Compound Interest Calculator
Calculate how your investments grow over time with compound interest. Add regular contributions, compare compounding frequencies, and see your future balance.
Mortgage Calculator
Calculate your monthly mortgage payment, see the full amortization schedule, and understand how much house you can afford. Free, no signup required.
Retirement Calculator
Calculate how much you need to retire, your FIRE number, and whether you are on track. See projections for your retirement savings growth over time.
Debt Payoff Calculator
Calculate how fast you can pay off your debt with extra payments. See how much interest you will save and when you will be debt-free.
Savings Goal Calculator
Calculate how much you need to save each month to reach your financial goal. See how different timelines and interest rates affect your required savings.
Investment Return Calculator
Calculate your investment returns including ROI, CAGR, and total gains. Compare performance across different time periods and see annualized returns.
Loan Comparison Calculator
Compare up to 3 loan offers side-by-side. See which loan has the lowest total cost, monthly payment, and interest charges to make the best borrowing decision.
Net Worth Calculator
Calculate your net worth by adding up your assets and subtracting liabilities. See your complete financial picture and track progress over time.
Emergency Fund Calculator
Calculate your ideal emergency fund based on risk tolerance, employability, and household situation. Get a personalized savings target in months of expenses.
Education Savings Calculator
Calculate how much to save for university or college. Factor in tuition inflation, investment returns, and see if you're on track for education costs.
Paycheck Calculator
Calculate your take-home pay after taxes and deductions. Enter your income tax brackets to see how much of your salary goes to taxes vs take-home.
Credit Card Payoff Calculator
Calculate how long it will take to pay off your credit card and how much interest you'll pay. See how extra payments can save you money and time.
Hourly to Salary Calculator
Convert hourly wage to annual salary and vice versa. See how much you make yearly, monthly, and weekly based on your hourly rate and hours worked.
Inflation Calculator
Calculate how inflation affects your money over time. See what today's dollars will be worth in the future and what past amounts equal in today's value.
Math (8 calculators)
Percentage Calculator
Calculate percentages easily. Find what percent one number is of another, calculate percentage increase/decrease, and solve any percentage problem.
Discount Calculator
Calculate the sale price after a discount and see how much you save. Works with percentage off, dollar off, and multiple discounts.
GPA Calculator
Calculate your GPA (Grade Point Average) for a semester or cumulative. Enter your grades and credit hours to find your GPA on a 4.0 scale.
Unit Price Calculator
Calculate and compare unit prices to find the best deal. Compare products of different sizes and prices to see which offers better value per unit.
Sales Tax Calculator
Calculate sales tax for any purchase. Enter the price and tax rate to find the total cost, or work backwards from the total to find the pre-tax price.
Grade Calculator
Calculate your current grade and what you need on the final exam. Enter assignment scores and weights to find your overall grade in any class.
Statistics Calculator
Calculate mean, median, mode, range, variance, and standard deviation for any dataset. Free statistics calculator with step-by-step results.
Fraction Calculator
Calculate fractions with step-by-step solutions. Add, subtract, multiply, or divide fractions and mixed numbers. Simplify to lowest terms.
Conversion (9 calculators)
Temperature Converter
Convert temperatures between Celsius, Fahrenheit, and Kelvin. Instant conversion with formulas and common reference points.
Length Converter
Convert length and distance between inches, feet, yards, miles, millimeters, centimeters, meters, and kilometers instantly.
Weight Converter
Convert weight and mass between pounds, kilograms, ounces, grams, stones, and tons. Free online weight converter.
Volume Converter
Convert volume between gallons, liters, quarts, pints, cups, fluid ounces, and milliliters. Free online volume converter.
Area Converter
Convert area between square feet, square meters, acres, hectares, and square yards. Free online area converter for real estate and land.
Speed Converter
Convert speed between miles per hour, kilometers per hour, meters per second, knots, and feet per second. Free online speed converter.
Shoe Size Converter
Convert shoe sizes between US, EU, UK, and Japanese sizing. Works for men's and women's shoes. Free instant conversion with size chart reference.
Clothing Size Converter
Convert clothing sizes between US, EU, and UK for t-shirts, jeans, dresses, and trousers. Includes size charts for men's and women's apparel.
Bra Size Converter
Convert bra sizes between US, EU, and UK sizing systems. Find your international bra size with band and cup conversions plus sister size alternatives.
Health & Fitness (17 calculators)
BMI Calculator
Calculate your Body Mass Index (BMI) using your height and weight. See where you fall on the BMI scale and understand what your number means.
Calorie Calculator
Calculate how many calories you need per day based on your age, weight, height, and activity level. Find your TDEE for weight loss, maintenance, or gain.
Pregnancy Due Date Calculator
Calculate your pregnancy due date based on your last menstrual period or conception date. See how many weeks pregnant you are and important milestones.
Body Fat Calculator
Calculate your body fat percentage using the U.S. Navy method. Enter your measurements to get an accurate estimate of your body composition.
Sleep Calculator
Calculate the best time to sleep or wake up based on sleep cycles. Wake up feeling refreshed by timing your sleep to complete full 90-minute cycles.
Pace Calculator
Calculate running pace, finish time, or distance. Perfect for runners and joggers training for races. Find your pace per mile or per kilometer.
Water Intake Calculator
Calculate how much water you should drink daily based on your weight, activity level, and climate. Get personalized hydration recommendations.
Ideal Weight Calculator
Calculate your ideal body weight based on height and gender using multiple medical formulas. Find your healthy weight range.
Heart Rate Zone Calculator
Calculate your target heart rate zones for exercise. Find your fat-burning, cardio, and peak zones based on age and fitness level.
UV Index Sunburn Timer
Calculate how long until sunburn based on UV index, skin type, and sunscreen SPF. Uses minimal erythemal dose (MED) data for Fitzpatrick skin types.
Smog in Cigarettes Calculator
Convert air pollution (PM2.5) to cigarettes per day equivalent. 22 µg/m³ of PM2.5 equals about 1 cigarette daily based on Berkeley Earth research.
Blood Alcohol Content (BAC) Estimator
Estimate your blood alcohol content (BAC) based on drinks consumed, body weight, and time elapsed. Uses the Widmark formula for educational purposes only.
Burn Off That Donut Calculator
Find out how long you need to exercise to burn off calories from food. Enter calories and your weight to see exercise times for walking, running, cycling, and more.
Junk Food to Exercise Converter
See how much exercise it takes to burn off popular junk foods. Pick pizza, burgers, fries, or donuts and find out how long to walk, run, or cycle to burn it off.
Sleep Debt Calculator
Calculate your weekly sleep debt by entering your target hours and actual sleep for each day. Get a personalized catch-up plan to recover from sleep deprivation.
Bike Size Calculator
Calculate your ideal bike frame size based on inseam and height. Works for road bikes, mountain bikes, and hybrids with recommended wheel sizes and saddle height.
Pokémon GO Weight Loss Calculator
Calculate calories burned and distance walked playing Pokémon GO. Enter play time and walking pace to see your workout equivalent and how many eggs you can hatch.
Date & Time (2 calculators)
Age Calculator
Calculate your exact age in years, months, and days. Discover fun facts like total heartbeats, breaths, and hours lived. Free age calculator with birthday countdown.
Date Calculator
Calculate the number of days between two dates or add/subtract days from a date. Find out how many days until an event or between important dates.
Home & DIY (14 calculators)
Rental Property Investment Calculator
Analyze rental property returns with gross yield, after-tax yield, cap rate, and cash flow. Compare investment metrics to evaluate real estate deals.
Home Affordability Calculator
Find out how much house you can afford based on your income, debts, and down payment. Get a realistic home buying budget with monthly payment estimates.
Rent vs Buy Calculator
Compare the financial impact of renting vs buying a home. See the break-even point and total costs over time to make an informed housing decision.
Square Footage Calculator
Calculate square footage for rooms, flooring, painting, and landscaping. Enter length and width to find total area in square feet or square meters.
Paint Calculator
Calculate how much paint you need for your room or project. Enter room dimensions and get accurate estimates for gallons needed, including doors and windows.
Electricity Cost Calculator
Calculate how much electricity an appliance uses and costs. Enter wattage and hours of use to find daily, monthly, and yearly energy costs.
Concrete Calculator
Calculate how much concrete you need for your project. Enter dimensions to find cubic metres or number of bags needed for slabs, footings, and posts.
Flooring Calculator
Calculate how much flooring material you need and estimate costs. Works for hardwood, laminate, tile, and carpet with waste factor included.
Pool Volume Calculator
Calculate pool water volume in litres or gallons. Works for rectangular, round, and oval pools. Essential for chemical dosing and water costs.
Wallpaper Calculator
Calculate how many rolls of wallpaper you need for a room. Accounts for pattern repeat, windows, doors, and waste factor.
Mulch Calculator
Calculate how much mulch you need in cubic yards or bags. Enter bed dimensions and depth to get accurate mulch estimates with cost.
Lawn Fertiliser Planner
Calculate how much lawn fertiliser to apply based on your lawn size and nitrogen requirements. Based on university extension service recommendations.
Leaky Faucet Calculator
Calculate how much water and money a dripping faucet wastes. Based on USGS data showing about 0.25 mL per drip, or 4000 drips per litre.
Rainwater Harvesting Calculator
Calculate how much rainwater you can collect from your roof. Enter roof area and local rainfall to estimate annual yield in litres.
Auto (3 calculators)
Auto Loan Calculator
Calculate your monthly car payment, total interest, and see an amortization schedule. Compare loan terms to find the best auto financing for your budget.
Fuel Cost Calculator
Calculate how much fuel will cost for your trip. Enter distance, fuel efficiency, and fuel price to estimate your fuel expenses for any journey.
MPG Calculator
Calculate your vehicle's fuel efficiency in miles per gallon. Track your gas mileage, compare fill-ups, and monitor your car's fuel economy over time.
Cooking (4 calculators)
Recipe Scaler Calculator
Scale any recipe to serve more or fewer people. Enter the original serving size and ingredient amounts, then adjust to your desired number of servings.
Cooking Conversion Calculator
Convert cooking measurements between cups, tablespoons, teaspoons, milliliters, ounces, and grams. Essential kitchen unit converter.
Baking Pan Converter
Convert recipes between different baking pan sizes. Calculate ingredient adjustments when substituting round, square, or rectangular pans.
Perfect Egg Boiling Calculator
Calculate the perfect boiling time for your eggs based on size, starting temperature, altitude, and desired doneness. Get soft, medium, or hard-boiled eggs every time.
Science (25 calculators)
Drake Equation Explorer
Explore the Drake equation to estimate communicative civilizations in our galaxy. Adjust all 7 parameters and see how each factor affects the final estimate.
Asteroid Impact Simulator
Calculate asteroid impact energy, TNT equivalent, and crater size. Enter diameter, density, and velocity to simulate cosmic collisions with simplified physics.
Nuclear Blast Effects Calculator
Calculate nuclear blast radii for different overpressure thresholds. Enter yield in kilotons to see fireball size and damage zones using cube-root scaling physics.
Weight on Other Worlds
Find your weight on the Moon, Mars, Jupiter, and other planets. Enter your Earth weight or mass to see what you would weigh across the solar system.
Age on Other Planets
Find your age in planetary years on Mars, Venus, Jupiter and more. Enter your age in Earth years to see how many birthdays you'd have on each planet.
Space Travel Time Calculator
Calculate how long it would take to travel to the Moon, Mars, or other destinations at various speeds. Compare walking, driving, rocket, and light speed travel times.
Horizon & Earth Curvature Calculator
Calculate distance to the horizon from any height, plus how much of a distant object is hidden by Earth's curvature. Educational tool for understanding our spherical planet.
Day/Night Terminator Calculator
Calculate the position of the day/night terminator line on Earth for any date and time. Find the subsolar point and see which parts of the world are in daylight.
Relativity Time Dilation Calculator
Calculate relativistic time dilation using the Lorentz factor. Enter speed as a fraction of light speed to see how time slows down for fast-moving objects.
Relativistic Doppler Shift Calculator
Calculate the velocity needed to shift light from one wavelength to another using the relativistic Doppler effect. See red-to-green light shift velocity.
Escape Velocity Calculator
Calculate escape velocity from any spherical body. Enter mass and radius to find the minimum speed needed to escape gravitational pull without further propulsion.
Dinosaur Speed Estimator
Estimate dinosaur running speed from trackway fossils using Alexander's method. Enter stride length and hip height to calculate how fast dinosaurs moved.
Falling Object Calculator
Calculate terminal velocity, impact speed, and energy for falling objects with air resistance. Test the penny-drop myth with real physics.
Sound Travel Time Calculator
Calculate how long sound takes to travel any distance. Find thunder delay from lightning distance, echo times, and speed of sound in air, water, and steel.
Human Scale Universe Calculator
Scale the solar system to everyday objects. If the Sun was a basketball, where would Earth be? Visualize cosmic distances in terms you can actually picture.
Pendulum Calculator
Calculate pendulum period and frequency from length. Find how long a pendulum takes to swing, design a grandfather clock, or understand harmonic motion physics.
Ruler Drop Reaction Time Calculator
Calculate your reaction time using the classic ruler drop test. Enter the catch distance to find your reflexes in milliseconds. A fun physics experiment anyone can do.
Black Hole Calculator
Calculate the Schwarzschild radius (event horizon) for any mass. What if Earth became a black hole? Find out how small it would be and explore black hole physics.
Ecological Footprint Calculator
Calculate your ecological footprint and discover how many Earths we'd need if everyone lived like you. Take this quick quiz based on Global Footprint Network methodology.
Flight Carbon Footprint Calculator
Calculate your flight's CO2 emissions. Enter distance and cabin class to see kg of carbon dioxide per passenger. Based on ICAO methodology.
Water Footprint of Food Calculator
Calculate the hidden water cost of your meal. See how many litres of water are needed to produce beef, chicken, rice, vegetables, and more using Water Footprint Network data.
Plastic Waste Calculator
Calculate how much plastic waste you generate per year. Count bottles, bags, and containers to estimate your annual plastic footprint in kilograms.
Lifetime Trash Calculator
Calculate how much trash you'll generate in your lifetime. Based on World Bank waste data averaging 0.79 kg per person per day globally.
Tree Carbon Offset Calculator
Calculate how many trees you need to offset your carbon emissions. Based on USDA data showing mature trees absorb about 22 kg (48 lbs) of CO2 per year.
Earthquake Energy Calculator
Convert earthquake magnitude to energy in Joules and TNT equivalents. Uses the Gutenberg-Richter relation to show the immense power of seismic events.
Business (4 calculators)
Break-Even Calculator
Calculate how many units you need to sell or revenue required to break even. Essential for business planning, pricing, and startup financial projections.
Tip Calculator
Calculate the tip amount and split the bill between multiple people. Quickly figure out 15%, 18%, 20% tips or enter a custom percentage.
Margin & Markup Calculator
Calculate profit margin and markup percentage. Convert between margin and markup, find selling price from cost, or calculate cost from selling price.
Profit Margin Calculator
Calculate profit margin, markup, and gross profit for your business. Enter cost and selling price to find margin percentage and optimize pricing.
Fun & Hypothetical (41 calculators)
LEGO House Calculator
Calculate how many LEGO bricks you need to build a life-size house. Get brick counts, total cost, weight, and build time estimates for any home size.
3D-Printed Home Calculator
Calculate how many 3D-printed bricks your home needs and how long it would take to print. Compare desktop printers vs industrial construction printers.
"Up" Balloon Lift Calculator
Calculate how many helium balloons you need to lift anything - yourself, your pet, or your house like in Pixar's Up. Based on real balloon lift physics.
Asteroid Hit Odds Calculator
Calculate the odds of an asteroid hitting your house. Based on real data showing 1 in 2.2 trillion annual odds for a typical home footprint.
Border Wall Comparator Calculator
Compare any construction project length and cost to the US-Mexico border wall. Based on 3,145 km border length and $21.6B estimated cost.
Christmas Lights Calculator
Calculate how many Christmas lights you need for your tree or house outline. Get bulb counts and string length estimates for any size.
Tree Leaf Counter Calculator
Estimate how many leaves are on a tree using crown diameter and Leaf Area Index (LAI). Based on NASA forestry data and botanical research.
Weird Units Converter
Convert measurements to weird and wacky units like Harry Potter books, llama spits, LEGO bricks, and football fields. A fun way to visualize any measurement.
Ant Army Lift Calculator
Calculate how many ants would be needed to lift any object. Based on real data that ants can lift 50 times their body weight.
Rubik's Cube Probability Calculator
Calculate the probability of solving a Rubik's Cube with random moves. With 43 quintillion possible states, discover why luck alone won't cut it.
Cash Stack Visualiser
Visualise any cash amount as a physical stack. See how high your money would stack, how much it weighs, and how many briefcases you need to carry it.
Football Fields & Eiffel Towers
Convert any distance or area into fun, relatable units like football fields, Eiffel Towers, and Central Parks. Make large measurements easy to visualize.
Olympic Swimming Pool Volume Converter
Convert any volume into Olympic swimming pools. Enter litres, cubic metres, or US gallons to see how many Olympic pools your volume equals. A fun way to visualize large volumes.
Lightning Strike Odds Calculator
Calculate your odds of being struck by lightning based on your lifestyle. NWS data shows 1 in 1.2 million annual odds for average US residents.
Shark Attack Probability Calculator
Calculate your shark attack odds based on your ocean activities. Based on International Shark Attack File data from the Florida Museum.
Meteorite Strike Chance Calculator
Calculate your odds of being hit by a meteorite. Based on estimates showing about 1 in 250,000 lifetime odds for an individual person.
Antipodal Point Calculator
Find the exact point on the opposite side of Earth from any location. Select a city or enter coordinates to discover your antipode.
World Population at Birth Calculator
Discover the world population when you were born and how much it's grown. Based on UN World Population Prospects historical data.
Chocolate Toxicity Calculator for Dogs
Calculate if your dog ate a dangerous amount of chocolate. Enter dog weight and chocolate type/amount to assess theobromine toxicity risk. For emergencies, call your vet.
Life Expectancy Calculator
Get a fun estimate of your life expectancy based on lifestyle factors like smoking, exercise, diet, and sleep. For entertainment purposes only - not medical advice.
Lifetime Heartbeat Counter
Calculate how many times your heart has beaten in your lifetime. Enter your age and resting heart rate to see your total heartbeats and projections to age 80.
Total Breaths Taken Calculator
Calculate how many breaths you have taken in your lifetime. Enter your age and breathing rate to see your total breaths and air volume inhaled since birth.
Blood Pumped in a Lifetime Calculator
Calculate how much blood your heart has pumped in your lifetime. See the total volume in liters, bathtubs, and Olympic pools based on your age and cardiac output.
Human Body Elemental Value Calculator
Calculate the raw material value of elements in your body. See how much your oxygen, carbon, hydrogen, and other elements would be worth at industrial prices.
Lifetime Water Consumption Calculator
Calculate how much water you have consumed in your lifetime. See your total intake in liters, bottles, bathtubs, and more based on your age and daily fluid intake (all beverages).
Lost Socks Probability Calculator
Calculate your weekly sock loss probability using the Sock Loss Index. Enter household size and laundry habits to predict how many socks you lose each year.
Pizza Size Value Calculator
Compare pizza sizes and prices to find the best value. Calculate cost per square inch and discover which size gives you more pizza for your money.
Social Media Time Alternatives Calculator
See what you could achieve with your social media time. Convert daily scrolling into books read, languages learned, and other meaningful alternatives.
Binge-Watch Marathon Planner
Plan your TV marathon with this binge-watch calculator. Enter episodes and runtime to see total watch time, finish date, and schedule with breaks and sleep.
Movie Marathon Scheduler
Plan your movie marathon with this scheduler. Add multiple movies, set break times, and get a complete viewing schedule with finish time. Perfect for themed marathons.
Santa Delivery Speed Calculator
Calculate the ridiculous speed Santa needs to deliver presents worldwide. See stops per second, Mach number, and g-forces for his magical Christmas journey.
Height in Lightsabers Calculator
Convert your height into fun units like lightsabers, LEGO minifigs, Harry Potter books, bananas, and more. A playful way to visualize measurements!
Hogwarts Tuition Calculator
Calculate the cost of attending Hogwarts School of Witchcraft and Wizardry. Estimate tuition, supplies, wands, broomsticks, and total 7-year magical education costs.
Weight in Eyeballs Calculator
Convert any weight into weird equivalents like human eyeballs, elephants, blue whales, or cats. A fun and memorable way to visualize mass and weight comparisons.
Despacito Potato Cooker Calculator
How many times must you play Despacito to cook a potato? Calculate the energy and time needed to heat food using your microwave. A fun physics calculator.
1 Billion Seconds Birthday Calculator
Find out when you turn 1 billion seconds old! Enter your birth date to discover this unique milestone - approximately 31 years and 8 months after birth.
Love Compatibility Calculator
Calculate a playful love compatibility score. Enter two names and birthdays for a deterministic rating that is just for fun.
Lifetime Commute Counter
Calculate your total lifetime commute time, distance, and cost. See how much of your life is spent commuting and compare remote work scenarios.
Waiting-in-Line Time Calculator
Calculate how much of your life you spend waiting in lines. Add up daily waiting for stores, traffic, appointments, and more to see the shocking total.
Betting Odds Calculator
Calculate expected value and implied probability of bets. Enter odds and your probability estimate to see if a bet has positive or negative expected value.
Casino Expected Loss Calculator
Calculate your expected casino losses over time. Choose from 20+ games, enter your bet size and session length to see expected loss, risk of ruin, and chance of winning big.