Calculators

Calendar, Date & Time Calculators

Age Calculator

Free age calculator: find out exactly how old you are in years, months, weeks, days, hours and minutes from your date of birth, updated to today.

Days Between Two Dates Calculator

Free days between two dates calculator: find the exact number of years, months, weeks and days between any two dates, including or excluding the end day.

Leap Year Calculator

Free leap year calculator: instantly check whether any year is a leap year, see the next leap years, and learn the simple rule behind them.

Sunrise-Sunset Calculator

Free sunrise and sunset calculator: find the exact sunrise, sunset and day length for any date and any location on Earth, with twilight times too.

What day is it? Calculator

Free what day is it calculator: find the day of the week for any past or future date, from your birthday to a historical event, instantly.

What’s the Current Week Number? Calculator

Free week number calculator: find out what week of the year it is today, whether it is odd or even, and the ISO week number for any date.

When is Friday the 13th? Calculator

Free Friday the 13th calculator: find out when the next Friday the 13th falls, and every Friday the 13th in any past or future year.

Health & Fitness Calculators

Bicycle Frame Size Calculator

Free bicycle frame size calculator: find your ideal bike frame size from your height and inseam for road, mountain, hybrid and city bikes.

Blood Pressure Calculator

Free blood pressure calculator: check whether your systolic and diastolic readings are normal, elevated or high for your age, with a blood pressure chart.

BMI Calculator

Free online BMI calculator: find your body mass index from height and weight, see your healthy weight range, and check it in metric or imperial units.

Body Surface Area Calculator

Free body surface area (BSA) calculator: work out your BSA in m² from height and weight using the Du Bois, Mosteller, Haycock and Gehan-George formulas.

Diabetes Risk Calculator

Free diabetes risk calculator: estimate your risk of type 2 diabetes in under a minute and get a clear risk score based on validated health factors.

Fat-Burning Heart Rate Calculator

Free fat-burning heart rate calculator: find your ideal heart rate zone for burning fat based on your age and sex, in beats per minute.

Ideal Weight Calculator

Free online ideal weight calculator: find your ideal body weight from height, age and gender using 6 trusted formulas, in metric and imperial units.

Waist-to-Hip Ratio Calculator

Free waist-to-hip ratio (WHR) calculator: divide your waist by your hip measurement to find your body shape and health risk category in seconds.

Pregnancy Calculators

Baby Eye Color Calculator

Free baby eye color calculator: predict your baby's likely eye color from the eye colors of both parents, with the probability of brown, blue and green.

Blood Type Calculator

Free blood type calculator: predict your baby's possible blood type and Rh factor from the blood groups of both parents, with the odds of each.

Pregnancy Due Date Calculator

Free pregnancy due date calculator: estimate your due date, see how many weeks pregnant you are, and find out when your baby was likely conceived.

Financial Calculators

Compound Interest Calculator

Free compound interest calculator: see how your savings or investment grows over time with compound interest, including regular deposits and any frequency.

Loan Calculator

Free loan calculator: work out your monthly payment, total interest and full amortization schedule from the loan amount, interest rate and term, in any currency.

Savings Goal Calculator

Free savings goal calculator: find out how long it will take to reach a savings target from your monthly deposit, current savings and interest rate.

TDEE Calculator

Free TDEE calculator: find your daily calorie needs (BMR and TDEE) and macro targets from your age, sex, height, weight and activity, in metric or imperial.

Ovulation Calculator

Free ovulation calculator: find your fertile window, your most likely ovulation day and your next period from the date of your last period and cycle length.

Body Fat Calculator

Free body fat calculator: estimate your body fat percentage with the US Navy method from a few tape measurements, in metric or imperial units.

Water Intake Calculator

Free water intake calculator: find out how much water you should drink each day based on your body weight and daily exercise, shown in litres and cups.

Electricity Cost Calculator

Free electricity cost calculator: work out the running cost of any appliance from its power in watts, hours of use and your price per kWh, per day, month and year.

Pace Calculator

Free running pace calculator: work out your pace, speed, time or distance for a run, in minutes per km or per mile, for training and races.

Pet Age Calculator

Free pet age calculator: convert your dog or cat age into human years using a realistic, size-aware formula, and see how old your pet really is.

Sleep Calculator

Free sleep calculator: find the best times to go to bed or wake up based on 90-minute sleep cycles, so you wake up refreshed instead of groggy.

Fuel Cost Calculator

Free fuel cost calculator: estimate the fuel cost of any trip from distance, fuel economy and price per litre or gallon, in metric or imperial units.

Tip Calculator

Free online tip calculator: work out the tip and total for any bill, choose your tip percentage, and split the cost evenly between any number of people.

VAT Calculator

Free online VAT calculator: add VAT to a net price or remove VAT from a gross price at any rate, with the net, VAT amount and gross shown instantly.

Math Calculators

Circle Area & Circumference Calculator

Free circle calculator: find the area and circumference of a circle from its radius or diameter instantly, with results in your preferred unit of measurement.

Cylinder Volume and Surface Area Calculator

Free cylinder volume and surface area calculator: enter the radius and height to get the volume and total surface area of a cylinder instantly, in any unit.

Decimal to Fraction Calculator

Free decimal to fraction calculator: convert any decimal into a fraction in its simplest form, including repeating decimals, with the steps shown.

Fraction Calculator

Free online fraction calculator: add, subtract, multiply and divide fractions and get the simplified result with a clear step-by-step explanation.

Greatest Common Divisor Calculator

Free greatest common divisor calculator: find the GCD (highest common factor) of two or more numbers instantly, with the calculation explained.

Online Basic Calculator

Free online basic calculator: add, subtract, multiply and divide any numbers quickly, using your mouse or keyboard, with no app to install.

Percentage Calculator

Free online percentage calculator: find what is X% of Y, what percent X is of Y, and percentage increase or decrease, with instant step-by-step answers.

Percentage Increase Calculator

Free percentage increase calculator: find the percentage change between two numbers, whether it is a rise or a fall, with a clear step-by-step result.

Scientific Calculator

Free online scientific calculator: handle powers, roots, logarithms, trigonometry and more, plus everyday arithmetic, right in your browser.

Other Calculators

Alcohol Dilution Calculator

Free alcohol dilution calculator: find out exactly how much water to add to lower a spirit to your target ABV, in litres or any volume unit.

BAC Calculator

Free online BAC calculator: estimate your blood alcohol content from your drinks, weight, sex and time, and see roughly when you will be sober enough to drive.

Biorhythm Calculator

Free biorhythm calculator: chart your physical, emotional and intellectual cycles from your date of birth and see your highs, lows and critical days.

Character and Word Counter Calculator

Free character and word counter: paste your text to instantly count characters, words, and characters with or without spaces, right in your browser.

Download Time Calculator

Free download time calculator: work out how long any file will take to download at your internet speed, from kilobits to gigabits per second.

Infrared Heater Calculator

Free infrared heater calculator: find the wattage of infrared heater you need to warm a room based on its size and insulation, fast and easy.

Is there life on other planets? Calculator

Are we alone in the universe? This free calculator uses the Drake equation to estimate how many intelligent, communicating civilizations may exist in our galaxy.

Poker Hand Range Calculator

Free poker hand range calculator: build and visualise hand ranges, see the odds update instantly, and sharpen your Texas Hold'em strategy.

PSN Trophy Level Calculator

Free PSN trophy level calculator: find your PlayStation trophy level from your trophies and see exactly how many points you need for the next level.

Resistor Color Code Calculator

Free resistor color code calculator: read the resistance and tolerance of 4, 5 and 6-band resistors from their color bands, with charts to decode any value fast.

Room Heating Calculator

Free room heating calculator: estimate the heating power in kW or BTU you need for a room based on its size and insulation, to size a radiator or heater.

Tile Calculator

Free tile calculator: estimate exactly how many tiles you need to cover a floor or wall, allowing for the area, tile size and the gap between tiles.

Wind Chill Calculator

Free wind chill calculator: find the feels-like temperature from the air temperature and wind speed, in Celsius or Fahrenheit, using the official formula.

Zodiac Sign Calculator

Free zodiac sign calculator: enter your date of birth to find your star sign instantly, along with its dates, element and key personality traits.