Calculators

Free calculators for the everyday math you do not want to work out by hand. Find a percentage, work out an age from a birth date, check a loan payment, or change units like Celsius to Fahrenheit. Each one runs in your browser and shows the answer as you type. Nothing you enter is sent anywhere, so your numbers stay private. These tools are made to be simple: a couple of boxes, a clear result, and a short note on how the math works. They are useful for school, shopping, budgets, and quick checks at work. Pick a calculator below. There is no account to make and no limit on how often you use it.

• Age Calculator Find your exact age in years, months, and days, plus the day of the week you were born.
• Amortization Calculator Build a full month-by-month amortization schedule for any loan.
• Area Calculator Work out the area of a rectangle, circle, triangle, and other shapes.
• BMI Calculator Work out your body mass index in metric or imperial units and see your weight category.
• BMR Calculator Work out your basal metabolic rate, the calories your body burns at complete rest.
• Body Fat Calculator Estimate your body fat percentage from a tape measure, using the US Navy method.
• BTU Calculator Estimate the BTU cooling capacity a room needs, as a rough guide.
• Budget Calculator See your monthly income against expenses, and what is left to save.
• Calorie Calculator Estimate the calories you need each day to maintain, lose, or gain weight.
• Calories Burned Calculator Estimate the calories you burn in any activity from your weight and time.
• Celsius to Fahrenheit Convert Celsius to Fahrenheit, with the formula and a table of common temperatures.
• Circle Calculator Enter any one circle measurement to find the radius, diameter, circumference, and area.
• Cm to Inches Convert centimetres to inches, with the formula and a table of common lengths.
• Commission Calculator Work out sales commission from an amount and a rate, plus total pay.
• Compound Interest Calculator Work out the future value of your money with compound interest.
• Conception Calculator Estimate your likely conception date from a due date or your last period.
• Concrete Calculator Work out how much concrete a slab needs, in cubic yards and bags.
• Credit Card Payoff Calculator Work out how long, and how much interest, to pay off a credit card.
• Days Between Dates Calculator Count the days, weeks, and months between any two dates, right in your browser.
• Debt Payoff Calculator Work out how long to clear a debt and what an extra payment saves.
• Density Calculator Work out density, mass, or volume from the other two.
• Dew Point Calculator Work out the dew point from temperature and relative humidity.
• Dice Roller Roll any number of dice online, from d4 to d100, with fair results.
• Discount Calculator Work out the final price and how much you save from any percentage discount.
• Down Payment Calculator Work out your down payment, loan amount, and loan-to-value.
• Due Date Calculator Estimate your due date from your last period, conception date, or an ultrasound.
• Exponent Calculator Raise any number to a power, including negative and fractional exponents.
• Fahrenheit to Celsius Convert Fahrenheit to Celsius, with the formula and a table of common temperatures.
• GCF Calculator Find the greatest common factor of two or more whole numbers.
• Heat Index Calculator Work out the heat index, how hot it really feels with humidity.
• Height Calculator Convert a height between feet and inches and centimetres, both directions.
• House Affordability Calculator Estimate the home price you can afford from your income and debts.
• Ideal Weight Calculator See a healthy weight for your height by the classic formulas and by BMI.
• Inches to Cm Convert inches to centimetres, with the formula and a table of common lengths.
• Inflation Calculator See how inflation changes the buying power of money over time.
• Interest Calculator See how much interest your money earns, simple versus compound.
• Investment Calculator Project the growth of an investment with regular contributions.
• Kg to Lbs Convert kilograms to pounds, with the formula and a table of common weights.
• Lbs to Kg Convert pounds to kilograms, with the formula and a table of common weights.
• LCM Calculator Find the least common multiple of two or more whole numbers.
• Lean Body Mass Calculator Estimate your lean body mass, the weight of everything except fat.
• Length Converter Convert between metric and imperial length units. Type in one box, the rest update.
• Loan Calculator Work out the monthly payment, total interest, and total cost of any fixed-rate loan.
• Macro Calculator Split your daily calories into grams of carbs, protein, and fat.
• Mean Median Mode Calculator Find the mean, median, mode, and range of a set of numbers.
• Mortgage Calculator Work out your monthly mortgage payment, with a full amortization schedule.
• Ovulation Calculator Estimate your ovulation day and fertile window from your cycle.
• Percentage Calculator Find a percentage of a number, a percent of a total, or the change between two numbers.
• Period Calculator Predict your next period dates from your cycle length and last period.
• Permutation and Combination Calculator Calculate permutations (nPr) and combinations (nCr), exact even for large numbers.
• Pregnancy Calculator See how far along you are, your trimester, and your due date.
• Pregnancy Weight Gain Calculator See the recommended weight gain for your pre-pregnancy BMI, by week.
• Probability Calculator Work out the probability of two independent events, with and, or, and not.
• Protein Calculator Work out how much protein you need each day, in grams, for your goal.
• Pythagorean Theorem Calculator Enter any two sides of a right triangle to find the third.
• Ratio Calculator Simplify a ratio to lowest terms, or solve a proportion for a missing value.
• ROI Calculator Work out return on investment, net profit, and annualized ROI.
• Roman Numerals Converter Convert numbers to Roman numerals and back, for 1 to 3999.
• Rounding Calculator Round to decimal places, to the nearest unit, or to significant figures.
• Salary Calculator Convert pay between hourly, weekly, monthly, and annual figures.
• Sample Size Calculator Work out how many people to survey for your confidence level and margin of error.
• Savings Calculator See how your savings grow with regular deposits and interest.
• Scientific Calculator A full scientific calculator with trig, logs, powers, roots, and constants.
• Shoe Size Conversion Convert shoe sizes between US, UK, EU, and centimetres, for men and women.
• Simple Interest Calculator Work out simple interest from the principal, rate, and time.
• Slope Calculator Find the slope between two points, with the line equation, distance, and angle.
• Speed Calculator Work out speed, distance, or time from the other two, in your units.
• Square Footage Calculator Work out the square footage of a room from its length and width.
• Standard Deviation Calculator Calculate sample or population standard deviation, with the difference explained.
• Student Loan Calculator Estimate your student loan payment, total interest, and total repaid.
• Take-Home Paycheck Calculator Estimate your net take-home pay from gross pay and your own deduction rates.
• Target Heart Rate Calculator Find your maximum heart rate and training zones in beats per minute.
• TDEE Calculator Work out the total calories you burn in a day, your maintenance level.
• Temperature Converter Convert between Celsius, Fahrenheit, and Kelvin. Type in any box, the others update.
• Tile Calculator Work out how many tiles you need, with a waste margin for cuts.
• Triangle Calculator Enter three sides to find the area, angles, perimeter, and type of a triangle.
• VAT Calculator Add VAT to a price or take it out, and see the net, VAT, and gross amounts.
• Volume Calculator Work out the volume of a box, sphere, cylinder, cone, and more.
• Weight Converter Convert between metric and imperial weight units. Type in one box, the rest update.
• Wind Chill Calculator Work out the wind chill, the feels-like temperature in cold, windy weather.
• Z-Score Calculator Calculate a z-score and its probability from a value, mean, and standard deviation.
• Average Calculator Find the mean, median, mode, range, and sum of any list of numbers.
• Date Calculator Add or subtract days, weeks, months, or years from any date.
• Day Counter Count the days until a future date, or since a past one, from today.
• Day of the Week Calculator Find out what day of the week any date falls on, past or future.
• Fraction Calculator Add, subtract, multiply, or divide two fractions, with the answer in simplest form.
• Fuel Cost Calculator Work out what fuel a trip will cost from the distance, economy, and fuel price.
• Gas Mileage Calculator Work out your fuel economy in MPG or litres per 100 km from distance and fuel used.
• GPA Calculator Work out your weighted and unweighted GPA on the 4.0 scale, one course per row.
• Grade Calculator Work out the score you need on the final exam to hit your target grade.
• Hours Calculator Work out the hours between a start and end time, minus your break.
• Random Number Generator Generate random numbers in a range, with or without repeats, in your browser.
• Sales Tax Calculator Add sales tax to a price, or work back to the price before tax from a total.
• Sleep Calculator Find good bedtimes for your wake-up time, using 90-minute sleep cycles.
• Time Calculator Add or subtract two durations in hours, minutes, and seconds.
• Tip Calculator Work out the tip, the total, and each person's share when you split the bill.