A complete library of free calculators for math, finance, health, time, conversions and everyday life. Pick a tool and start right away.
Arithmetic, percentages, algebra, geometry and advanced math.
Find a percentage of any value quickly and accurately.
Open calculatorSolve ax² + bx + c = 0 with the discriminant, roots and parabola vertex.
Open calculatorMeasure the percentage increase or decrease between two values.
Open calculatorCompute sine, cosine, tangent and reciprocal functions for an angle in degrees or radians.
Open calculatorCalculate the first and second derivative of a function at a point, with tangent and normal lines.
Open calculatorAdd, subtract, multiply or divide any two numbers and get the result instantly.
Open calculatorFind the hypotenuse of a right triangle from its legs, with perimeter and area.
Open calculatorCalculate a value after a percentage increase, including the increase amount.
Open calculatorCalculate a value after a percentage decrease, including the decrease amount.
Open calculatorSolve the linear equation ax + b = c step by step and verify the solution.
Open calculatorCalculate a function's limit at a point or at infinity, with one-sided limits and a continuity check.
Open calculatorCalculate a definite integral over an interval using Simpson's rule, with the average value.
Open calculatorFind the whole number when you know a part and its percentage.
Open calculatorFind the nth term and the sum of the first n terms of an arithmetic sequence.
Open calculatorCalculate a circle's diameter, circumference and area from its radius.
Open calculatorFind all three sides of a right triangle from an angle and one known side.
Open calculatorCalculate a logarithm in any base, with the natural and common logarithms and inverse relations.
Open calculatorEvaluate a full mathematical expression with parentheses, exponents and functions.
Open calculatorConvert any fraction to a decimal, with the simplified fraction and percentage.
Open calculatorConvert any decimal number to a simplified fraction and mixed number.
Open calculatorTest whether a number is prime, factor it, and list primes up to a limit.
Open calculatorSolve a system of two linear equations in two variables using determinants and identify its type.
Open calculatorSimplify the ratio between two numbers and see its value and each part's percentage.
Open calculatorCompare two values using absolute and relative percentage difference.
Open calculatorFind the nth term and sum of a geometric sequence, including the infinite sum when it converges.
Open calculatorCalculate an integer factorial with its digit count, trailing zeros and scientific notation.
Open calculatorFind the greatest common divisor of two or more numbers with the method explained.
Open calculatorFind the least common multiple of two or more numbers quickly.
Open calculatorCalculate powers, square roots, cube roots and nth roots.
Open calculatorApply a series of percentage increases and decreases and calculate the total change.
Open calculatorSolve the proportion a/b = c/x to find the unknown value x.
Open calculatorSplit an amount or quantity into shares according to a given ratio.
Open calculatorFactor ax² + bx + c and see its roots and factorization type.
Open calculatorCalculate a triangle's area from its base and height, with the doubled area.
Open calculatorCalculate a vector's magnitude, direction, unit vector and quadrant.
Open calculatorCalculate the number of permutations and combinations when choosing r items from n.
Open calculatorAdd, subtract, multiply and divide decimal numbers and see the result as a fraction.
Open calculatorConvert numbers to scientific and engineering notation, and back.
Open calculatorCalculate the unknown value in a direct proportion relationship.
Open calculatorCalculate the unknown value in an inverse proportion relationship.
Open calculatorSolve |ax + b| = c and see the number of solutions and both cases.
Open calculatorCalculate a rectangle's area, perimeter and diagonal from its length and width.
Open calculatorAdd, subtract or multiply two 2×2 matrices and see the determinant and trace.
Open calculatorAdd, subtract, multiply or divide two complex numbers, with modulus, argument and polar form.
Open calculatorEvaluate a chain of arithmetic operations while respecting multiplication and division precedence.
Open calculatorConvert mixed numbers to improper fractions and back, with simplification.
Open calculatorList the divisors of any number, their sum, and its first multiples.
Open calculatorCalculate the quotient and remainder of a division and verify the result.
Open calculatorCombine like terms to write a polynomial in simplest form, with its degree and leading coefficient.
Open calculatorCalculate the slope of a line through two points, its angle and its equation.
Open calculatorFind the third side and remaining angles of a triangle from two sides and the included angle.
Open calculatorConvert whole numbers between binary, octal, decimal and hexadecimal.
Open calculatorFind the absolute value of any number, its sign, and its additive inverse.
Open calculatorSplit a length according to the golden ratio and calculate the larger and smaller parts.
Open calculatorSolve a system of three linear equations in three variables using determinants.
Open calculatorEvaluate f(x) at a given value, with additional sample points.
Open calculatorCalculate the distance between two points in the coordinate plane, with horizontal and vertical differences.
Open calculatorCalculate the determinant of a 3×3 matrix with its trace and a cofactor.
Open calculatorCalculate the dot product, cross product and angle between two vectors in space.
Open calculatorRound any number to a whole number or a chosen decimal place.
Open calculatorAdd, subtract, multiply and divide fractions with simplified results.
Open calculatorCalculate the average of a set of values as a percentage of a reference value.
Open calculatorSolve the inequality ax + b ⋚ c and see the solution set in interval notation.
Open calculatorSolve a · bˣ = c using logarithms, with verification of the solution.
Open calculatorCalculate a sphere's volume, surface area and circumference from its radius.
Open calculatorSolve a non-right triangle with the law of sines from two angles and a side.
Open calculatorFind the inverse of a 2×2 matrix and its determinant, or check that it is not invertible.
Open calculatorPerform operations on negative and positive numbers and understand the sign rules.
Open calculatorSolve log_b(ax + c) = d by converting it to an exponential equation.
Open calculatorCalculate a cube's volume, surface area and diagonals from its side length.
Open calculatorApply the identity a² − b² = (a − b)(a + b) and compute the value and difference.
Open calculatorCompute f(g(x)) and g(f(x)) from two function expressions and an x value.
Open calculatorCalculate a cylinder's volume, lateral surface area and total surface area from radius and height.
Open calculatorCalculate a parallelogram's area and perimeter from its base, height and side.
Open calculatorCalculate a rectangular prism's volume, surface area and space diagonal.
Open calculatorCalculate the midpoint between two points and the distance between them.
Open calculatorCalculate a trapezoid's area, perimeter and median from its bases and height.
Open calculatorCalculate a cone's volume, surface area and slant height from radius and height.
Open calculatorCalculate a rhombus's area, side length and perimeter from its diagonals.
Open calculatorCalculate a regular polygon's perimeter, area and angles from its side count and side length.
Open calculatorTaxes, discounts, loans and interest.
Add VAT to an amount or extract it from a VAT-inclusive total.
Open calculatorFind the final price after one discount or two stacked discounts.
Open calculatorCalculate the monthly payment and total interest for any loan.
Open calculatorBody indicators, calories and nutrition, fitness and running, sleep, water, and pregnancy age.
Calculate your body mass index and healthy weight range for your height.
Open calculatorCalculate total daily energy expenditure from basal metabolic rate and activity level.
Open calculatorEstimate a daily calorie target for maintenance or gradual change, with a protective floor and a warning against aggressive restriction.
Open calculatorCalculate gestational age in weeks and days from a reference date, with trimester, progress and days remaining.
Open calculatorEstimate calories burned during an activity from weight, duration and intensity using MET values.
Open calculatorCalculate running pace per kilometer or mile from distance and time, with average speed.
Open calculatorCalculate basal metabolic rate with Mifflin-St Jeor, the energy your body needs at complete rest.
Open calculatorAdd up calories for common foods by weight using approximate reference nutrition values.
Open calculatorEstimate a daily fluid range from weight, exercise duration and climate, with a caution against overdrinking.
Open calculatorSee the weight ranges for each BMI category at your height, using WHO or Asia-Pacific cut-offs.
Open calculatorCalculate speed from distance and time in km/h, mph and m/s, with pace.
Open calculatorSplit daily calories across protein, carbohydrates and fat and get grams for each.
Open calculatorEstimate a daily protein range from your weight and activity level, with an approximate amount per meal.
Open calculatorEstimate body fat percentage with the US Navy circumference method, plus fat mass and lean mass.
Open calculatorCalculate sleep duration from bedtime to wake time, with optional naps and approximate sleep cycles.
Open calculatorCalculate waist-to-height ratio and see where it falls, plus the approximate waist limit at half your height.
Open calculatorEstimate an adult training heart-rate range using percent-of-max or Karvonen.
Open calculatorCalculate waist-to-hip ratio and compare it with approximate WHO adult thresholds.
Open calculatorFind the time needed for a distance at a given pace, or the distance covered in a given time.
Open calculatorPredict a race time from a previous distance and time using the Riegel formula, with clear limits.
Open calculatorCompare several published reference-weight formulas by height and sex, with a clear note on their limits.
Open calculatorPlan even, negative or positive race splits with per-split and half-race times.
Open calculatorCombine up to three splits or laps to calculate average speed, pace and your fastest and slowest split.
Open calculatorEstimate a daily fiber target by age and sex, with meal distribution and food examples.
Open calculatorCalculate calories from carbohydrates, protein, fat and alcohol using Atwater factors.
Open calculatorCalculate body surface area with the Mosteller and Du Bois formulas from height and weight.
Open calculatorEnter sleep hours for seven nights and get the average, total and number of short nights.
Open calculatorConvert per-serving label values into the amount you ate and the whole package, with approximate daily values.
Open calculatorCompare the fluids you drank with an estimated target from weight, activity and climate, without claiming a medical hydration measurement.
Open calculatorEstimate session and weekly training load from perceived exertion, duration and sessions.
Open calculatorAge, date differences, Gregorian and Hijri calendars, time zones, and event planning.
Convert dates between the Gregorian and Hijri calendars in both directions, with the weekday and a one-day variance note.
Open calculatorCalculate your age in years, months and days, and find your next birthday.
Open calculatorEstimate a due date from the last period, conception date or ultrasound scan, with a clear estimate disclaimer.
Open calculatorCompare the time in two cities, see the difference in hours and minutes, and view each local time.
Open calculatorCalculate your age in days, hours and minutes, with an optional birth time for greater precision.
Open calculatorA precise countdown to an event in days, hours and minutes, with the event name and weekday.
Open calculatorCount business days between two dates while excluding the weekly weekend and any official holidays you add.
Open calculatorA digital or analog clock shown as a floating layer over the page, draggable anywhere with multiple styles.
Open calculatorFind the estimated Hijri date for any Gregorian day, with year, month and day details and a moon-sighting note.
Open calculatorConvert a UTC date and time to the local time of any city, with the offset and weekday.
Open calculatorFind a project's finish date from the required working days, excluding the weekly weekend and official holidays.
Open calculatorA floating countdown clock: set minutes and seconds, start, pause, reset and drag it anywhere.
Open calculatorFind how many days remain until a date, with weeks and business days for future dates.
Open calculatorList expected public holidays for a country and year, with Gregorian dates, weekdays and a change notice.
Open calculatorPlan an international meeting: enter the start time in one city and the duration, then see start and end times in other cities.
Open calculatorFind how many weeks and days remain until a date, with the full date and weekday.
Open calculatorA floating stopwatch that measures elapsed time, draggable anywhere with start, pause and reset.
Open calculatorAdd a number of days to any date and get the new date and weekday.
Open calculatorFind how many days remain until the end of the year, with remaining business days and the year's remaining share.
Open calculatorConvert time between 12-hour and 24-hour formats, with a clear Arabic form and minutes since midnight.
Open calculatorCalculate net working hours between start and end times with a break deduction, including overnight shifts.
Open calculatorFind the number of days, weeks and months between any two dates.
Open calculatorSubtract a number of days from any date to find the earlier date and weekday.
Open calculatorFind the weekday for any Gregorian date, with its day-of-year number and week number.
Open calculatorCalculate overtime after breaks against standard working hours, with overnight shift support.
Open calculatorGenerate a schedule of installment due dates from the first payment date, count and frequency.
Open calculatorAdd months or years to a date and get the new date, with a note when the day is clamped to month end.
Open calculatorFind the number of days in any month and year, with the first and last weekday and leap-year status.
Open calculatorCalculate the time elapsed since a moment in days, hours and minutes, with a calendar breakdown in years and months.
Open calculatorCalculate actual school days in a term after excluding the weekly break and school holidays.
Open calculatorCompare two event dates, count the days between them, and see the countdown from today to each.
Open calculatorCheck whether a year is a leap year, with its length, February days and nearby leap years.
Open calculatorFind a task's end time from its start and duration, or its start from its end, with overnight detection.
Open calculatorGenerate a shift schedule for chosen days using two-shift, three-shift or 2-on/2-off patterns.
Open calculatorCalculate service or employment length between two dates in years, months and days, with total months and decimal years.
Open calculatorFind the ISO 8601 week number for any date, with the week's start, end and day position.
Open calculatorFind the day-of-year number, the days left, the elapsed percentage, and the week number.
Open calculatorLength and distance, weight and mass, area, volume, temperature and pressure, speed, energy, and data.
Convert temperature between Celsius, Fahrenheit and Kelvin accurately.
Open calculatorConvert between meters, feet, inches, kilometers, miles and more in one tool.
Open calculatorConvert between kilograms, pounds, ounces, tonnes and stones in one tool.
Open calculatorConvert between kilometers per hour, meters per second, miles per hour and feet per second.
Open calculatorConvert between millimeters, centimeters, meters and kilometers easily.
Open calculatorConvert power between watts, kilowatts, megawatts, mechanical horsepower and metric horsepower.
Open calculatorConvert time units between seconds, minutes, hours, days and weeks.
Open calculatorConvert between inches, feet, yards and miles with instant reference results.
Open calculatorConvert data storage units between bytes, kilobytes, megabytes, gigabytes and binary units.
Open calculatorConvert between milligrams, grams, kilograms and metric tonnes.
Open calculatorConvert between pascals, kilopascals, bars, atmospheres and PSI.
Open calculatorConvert between milliliters, liters, cubic centimeters and cubic meters.
Open calculatorConvert energy between joules, calories, kilocalories, watt-hours, kWh and BTU.
Open calculatorCalculate the geographic distance between two points using latitude and longitude.
Open calculatorConvert between pounds, ounces, stones and US short tons.
Open calculatorConvert between square centimeters, square meters, square kilometers and hectares.
Open calculatorConvert data transfer units with a clear explanation of the difference between bits and bytes.
Open calculatorConvert between hectares, feddans, acres and square meters with a clear feddan definition.
Open calculatorConvert between US gallons, UK gallons, liters and milliliters.
Open calculatorConvert angles between degrees, radians, gradians, turns, arcminutes and arcseconds.
Open calculatorConvert between square feet, square yards, square meters and acres.
Open calculatorConvert nautical miles to kilometers, miles and meters, with a reference value for knots when needed.
Open calculatorConvert kitchen measures between cups, tablespoons, teaspoons and milliliters.
Open calculatorConvert frequency between hertz, kilohertz, megahertz and gigahertz.
Open calculatorCalculate shipment volume, estimated weight and chargeable weight from dimensions and density.
Open calculatorConvert fuel volumes between liters, US and UK gallons, oil barrels and cubic meters.
Open calculatorConvert density between kg/m³, g/cm³, kg/L, lb/ft³ and lb/US gallon.
Open calculatorConvert between hectares, acres, feddans, dunams, ares and square meters.
Open calculatorCalculate hydrostatic pressure from liquid density, depth and gravitational acceleration.
Open calculatorConvert knots to kilometers per hour, miles per hour and meters per second.
Open calculatorConvert US and UK fluid ounces to milliliters, cups and liters.
Open calculatorConvert RPM to hertz, radians per second and degrees per second, and back.
Open calculatorConvert voltage between volts, millivolts and kilovolts.
Open calculatorConvert between astronomical units, light-years, parsecs, kilometers and miles.
Open calculatorConvert dunams using metric, Ottoman, Iraqi or Cypriot definitions, with comparisons in meters and hectares.
Open calculatorConvert volumetric flow between cubic meters per second, liters per minute, CFM and GPM.
Open calculatorConvert electric current between amperes, milliamperes and kiloamperes.
Open calculatorConvert acceleration between m/s², ft/s², g and km/h/s.
Open calculatorConvert gemstone carats to milligrams and grams accurately.
Open calculatorConvert vacuum and low-pressure units between pascals, millibars, torr and microns.
Open calculatorConvert electrical resistance between ohms, kilo-ohms and mega-ohms.
Open calculatorConvert torque between newton-meters, kilogram-force meters, pound-feet, pound-inches and dyne-centimeters.
Open calculatorConvert dynamic viscosity between pascal-seconds, millipascal-seconds, poise and centipoise.
Open calculatorConvert luminous intensity (cd) and illuminance (lux and fc) units with a clear explanation of their relationship.
Open calculatorTips, bills, fuel and sleep.
Areas, paint, tiles and concrete.
Averages, standard deviation and probability.
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