Online calculators

A percent of a number, a share, a markup, a discount, and the change between two numbers.

An annuity or a declining payment, the extra cost, and the schedule.

The payment and the extra cost from the flat price and the down payment.

Radius, diameter, circumference, and area, from any one of those quantities.

Body mass index and a weight range from the WHO boundaries.

How many calories you use at rest, by the Mifflin–St Jeor formula.

Wake time or bedtime from cycles of about 90 minutes.

Meters, inches, miles, versts, sazhens, and arshins.

Start, pause, laps, PDF, and full screen. Easy from a phone.

Calendar days and weekdays, with the endpoints included or not.

Addition, subtraction, multiplication, division, powers, and parentheses.

A random password in the browser, with nothing sent to a server.

Tip, total bill, and the amount per person.

Converts an integer between bases from 2 to 36.

An estimate of alcohol concentration by the Widmark formula.

Days until a holiday or your own date.

Voltage, current, resistance, and power.

A percent of a number, a share, a markup, a discount, and the change between two numbers.

One discount or two in a row, and a lookup of the price before the discount.

An annuity or a declining payment, the extra cost, and the schedule.

The payment and the extra cost from the flat price and the down payment.

The amount at the end of the term, with top-ups and different compounding.

How many pieces you must sell to cover the fixed costs.

The future price of the same goods, and what the amount can still buy.

Converts an amount at a rate you type yourself.

Tip, total bill, and the amount per person.

A price from cost, by markup or by margin.

How many years the amount takes to double at a given rate.

Equal yearly write-offs of an asset's value.

Pay divided by the number of hours.

An interest-free installment plan against a discount for paying cash.

Profit on one order after the fee, shipping, and ads.

How many times the amount grows at a yearly percent.

Radius, diameter, circumference, and area, from any one of those quantities.

From the base and the height, from three sides, or from two sides and the included angle.

Area, perimeter, and diagonal from two sides.

The midsegment times the height. The perimeter, when the non-parallel sides are known.

Finds the third side of a right triangle.

The discriminant and the roots of ax² + bx + c = 0.

Volume and surface area from the radius.

Volume, side area, and full surface of a pipe, a can, or a tank.

Volume, slant height, and surface area of a right circular cone.

Volume, surface area, and the space diagonal.

Finds x in the proportion a / b = c / x.

The greatest common divisor and the least common multiple of two integers.

The ordinary mean and the weighted mean of a list of numbers.

A root of a chosen degree, checked by raising it back.

The base to any integer or fractional power.

The product of all integers from 1 to n.

How many ways to choose k items from n.

A primality check and a factorization.

How many integers from 1 to n are coprime to n.

The digits added again until one digit remains.

Whether the sum of the digits, each to the power of the digit count, equals the number.

Converts an integer between bases from 2 to 36.

Converts between Roman notation and an ordinary number.

An integer quotient and a nonnegative remainder.

Addition, subtraction, multiplication, and division of common fractions.

An improper fraction as a whole number and a remainder.

Area and perimeter of a regular hexagon.

Volume of a cone with two radii.

Volume of a pyramid with two square bases.

Three angles from three sides.

A summary of a number list: mean, median, mode, and range.

How many standard deviations the value lies from the mean.

The value below which a given share of the series lies.

Bounds on the mean from the spread and the sample size.

How many answers you need for a set error on a share.

A linear link between two series, by Pearson.

The remainder of a power divided by a modulus.

A number whose product with this one leaves a remainder of 1.

A term and the sum of an arithmetic or a geometric progression.

Common, natural, binary, or a logarithm in a base you choose.

Sine, cosine, and tangent of an angle in degrees.

Sector area and arc length from the radius and the angle.

Volume, surface area, and the diagonal of a rectangular box.

Volume of a pyramid with a square base.

The arithmetic, geometric, and harmonic means.

Compares a number with the sum of its proper divisors.

How many ways there are to write n as a sum of positive integers, ignoring order.

How many ways there are to place n distinct items into k groups that are not empty.

A mean with a weight on each number.

One unknown in the equation PV = nRT.

The angle of refraction at the boundary of two media.

The first and second cosmic speeds for Earth, Mars, and the Moon.

Flow regime in a round pipe.

The percent of actual product relative to the theoretical amount.

Body mass index and a weight range from the WHO boundaries.

Four formulas: Devine, Robinson, Miller, and Hamwi.

How many calories you use at rest, by the Mifflin–St Jeor formula.

Intake for the day, the goal, and a rough split of protein, fat, and carbs.

About 30 mL per kilogram of weight, plus extra for the workout.

Grams of protein per day from weight and activity level.

Wake time or bedtime from cycles of about 90 minutes.

Zones from an estimate of maximum heart rate, or from the Karvonen formula.

eGFR from creatinine, the CKD-EPI 2021 equation.

From the last period, from conception, or from the age on an ultrasound.

An estimate of alcohol concentration by the Widmark formula.

The ovulation day and the fertile window from the cycle length.

Speed, pace, and a calorie guide for a walk.

Speed and energy use of a bicycle ride.

Calories from grams of protein, fat, and carbohydrate.

Recalculates the calories on the label for the actual weight.

How many kilocalories there are per gram of the food.

Compares foods by protein per 100 kilocalories.

How far the heart rate fell in the minute after exercise.

A stride estimate for walking and running, from height.

How much the same mass would weigh in a different gravity.

A frame-size guide from inseam.

Speed and rollout from the sprockets and cadence.

Meters, inches, miles, versts, sazhens, and arshins.

Kilograms, pounds, ounces, carats, poods.

Celsius, Fahrenheit, and kelvin.

Kilometers per hour, meters per second, miles, and knots.

Square meters, ares, hectares, acres, and desyatinas.

Liters, milliliters, gallons, cups, and cubic meters.

Gigabytes and gibibytes side by side, so 1000 and 1024 are not confused.

Seconds, minutes, hours, days, and mean months.

mmHg, pascals, bars, atmospheres, and psi.

Kilocalories, joules, watt-hours, and BTU.

Watts, kilowatts, and horsepower.

Kilograms per cubic metre and grams per cubic centimetre.

Hertz, kilohertz, and revolutions per minute.

Degrees, radians, gradians, and arcminutes.

Newtons, kilogram-force, and pound-force.

Pieces, dozens, grosses, and great hundreds.

Liters per 100 km from the tank and the distance, or the other way.

Gasoline, toll roads, and the amount per person.

The distance during the reaction, and the braking itself.

Hours and minutes from distance and speed.

The remaining price under a constant yearly decline.

How far the outer edge of the wheel moves outward.

Oil for a two-stroke mix.

Outside diameter, rollout length, and revolutions per kilometre.

The crosswind and headwind parts of the wind.

Volume, mix mass, and the number of bags with waste.

Liters for the walls after openings, coats, and waste.

How many tiles by the grid and by area, with waste for cuts.

Packs with an allowance for cuts and the leftover after laying.

Cubic meters, a cement guide, and the mass of the mix.

Room walls without windows and doors.

Kilograms of mix by layer thickness.

Rolls from the room perimeter and the strip height.

Sheet count from area and waste.

Packs of insulation from area and thickness.

Concrete volume of a rectangular strip.

Rod mass from diameter and length.

Mass of a steel pipe from the outside diameter and the wall.

Mass of a steel sheet from its size.

An estimate of a batch of screws from the size.

An estimate of bolt mass with an allowance for the head.

An estimate of nail mass from diameter and length.

Cement and sand for a volume of mortar.

Mass of a loose material from volume and bulk density.

Slope area from the building footprint and the angle.

Posts, bays, and the area of the panel.

Spacing of spotlights across the room.

Density from mass and volume.

Start, pause, laps, PDF, and full screen. Easy from a phone.

Calendar days and weekdays, with the endpoints included or not.

Full years, months, and days, and the time until the next birthday.

The tropical sign, using the usual date boundaries.

ISO week number and the week-numbering year.

A check by the Gregorian calendar rule.

Days until a holiday or your own date.

The date after a given number of days.

Weekdays between two dates, with no holidays.

Full years, months, and days between two dates.

Addition, subtraction, multiplication, division, powers, and parentheses.

A random password in the browser, with nothing sent to a server.

The average of the grades and, on a 5-point scale, the count of each mark.

Kilograms of meat and the number of skewers for the party.

Compares two pizzas by the price of a square centimetre.

Heads or tails, one flip or a series.

One integer, or several, inside the bounds you set.

Average grade and a proportional conversion to the 4.0 scale.

Converts fresh, active dry, and instant yeast.

Butter and vegetable oil in baking.

Converts dry rice to cooked rice and back.

Converts dry pasta to cooked pasta and back.

Salt for a brine, or the percent of a mix that is already made.

Water or coffee at a ratio of 1 to n.

Characters, words, and lines.

One item from the list, or several.

The lines are in random order.

Splits the lines into equal groups.

The shared lines, and what is in only one list.

Water and heating for one shower, at your rates.

The price of one page and of the whole run.

Pack mass from size and density.

Capacity from the kitchen volume and the air-change rate.

Voltage, current, resistance, and power.

Watts and kilowatt-hours from voltage and current.

Series and parallel connection of resistors.

Capacitance of a series connection and a parallel connection.

The divider output with a load or without one.

Heat to warm something, from mass, heat capacity, and the temperature gap.

How many times to fold a sheet to get thinner than the target.

The unknown in the equation C1×V1 = C2×V2.

Hardness from calcium and magnesium.

How many seeds a bed of a given area needs.