All Calculators

Calculate the volumetric flow rate through a sharp-edged orifice — Q = Cd·A·√(2gh). The discharge coefficient Cd (~0.62) accounts for the vena contracta.

Calculate the osmotic pressure (Π = iMRT) in atmospheres and kilopascals of a solution from the van 't Hoff factor, the molar concentration, and the temperature.

Calculate the distance to a star in parsecs and light-years from its annual parallax angle in arcseconds, using d = 1 / p.

Calculate the moment of inertia about a parallel axis with the parallel axis theorem: I = I_cm + m·d² in kg·m².

Calculate the total capacitance of two capacitors in parallel — they simply add: C = C1 + C2.

Calculate the equivalent inductance of two inductors in parallel, L_eq = (L1·L2)/(L1+L2), in henries from the two coil inductances.

Calculate the capacitance of a parallel-plate capacitor from its plate area, plate separation, and dielectric constant — C = ε₀ × εr × A / d.

Calculate the area of any parallelogram from its base and perpendicular height using the formula area = base × height.

Calculate the partial pressure of a gas using Dalton's law (P_i = mole fraction × total pressure) in kilopascals.

Calculate the output force of a hydraulic press with Pascal's principle (F2 = F1 × A2 / A1) from the input force and the two piston areas.

Work out your new pay and the size of the increase from a raise percentage — currency-agnostic, works for hourly or annual pay, and handles pay cuts too.

Calculate the period and frequency of a simple pendulum from its length — period = 2π√(L ÷ g) and frequency = 1 ÷ period.

Calculate the area, perimeter, apothem, and circumradius of a regular pentagon from its side length — area = ¼√(5(5+2√5))s², perimeter = 5s, apothem = s/(2·tan36°), circumradius = s/(2·sin36°).

Calculate the volume, cross-section area, and surface area of a regular pentagonal prism from the side length and prism length — volume = ¼√(5(5+2√5))·s²·L.

Calculate percent error between an experimental (measured) value and a theoretical (true) value — percent error = |measured − true| ÷ |true| × 100%.

Calculate the percent yield of a chemical reaction from the actual yield and the theoretical yield predicted by stoichiometry.

Calculate percentages in three modes: find a percentage of a number, find what percent one number is of another, or calculate percentage change between two values.

Calculate the percentage increase or decrease between an original value and a new value, with the absolute difference shown alongside.

Calculate the percentage difference between two values — a symmetric comparison relative to their average.

Calculate the percent error between a measured value and the accepted (true) value, plus the absolute error.

Calculate the pH (pH = −log₁₀([H⁺])) of an aqueous solution from its hydrogen-ion concentration, plus the matching pOH.

Calculate the energy of a photon (E = h·c / λ) in electronvolts and joules from its wavelength using the Planck–Einstein relation.

Calculate the momentum of a photon (p = h / λ) in kg·m/s from its wavelength in nanometres, using the Planck constant.

Work out the weight of any straight pipe run from its outside diameter, wall thickness, length and material. Metric and imperial, seven materials.

Convert pixels to inches, centimetres, millimetres or points at any DPI — and back. Free, instant, and it shows the pixel density the answer depends on.

Convert a point between polar and rectangular coordinates in either direction, in degrees or radians.

Calculate each interior angle of a regular polygon ((n − 2)·180 / n) and the sum of all interior angles ((n − 2)·180) from the number of sides.

Calculate the gravitational potential energy of an object from its mass and height — PE = m × g × h, with g = 9.80665 m/s², in joules.

Convert power between metric, imperial, and thermal units — watts, kilowatts, megawatts, mechanical horsepower, metric horsepower (PS), and BTU per hour.

Calculate the power dissipated by a resistor (P = I²R) in watts and the voltage drop across it from the current and resistance.

Calculate the power factor, phase angle, and reactive power of an AC circuit from its real and apparent power — PF = P / S, φ = arccos(P / S), Q = √(S² − P²).

Calculate power from work and time — power = work ÷ time, in watts (W), with the equivalent in horsepower (hp).

Calculate power-to-weight ratio in watts per kilogram and horsepower per tonne and per pound, for cars, bikes, and cycling.

Calculate the pixel density (PPI) and dot pitch of any display from its pixel resolution and physical diagonal in inches.

Calculate parts per million (ppm = mass of solute ÷ mass of solution × 1,000,000) and the equivalent percentage from a solute mass and a solution mass.

Convert pressure between pascal, bar, atmosphere, psi, mmHg, and more — instantly and with exact, pascal-based conversion factors.

Calculate pressure from force and area — pressure = force ÷ area, in pascals (Pa).

Calculate the price elasticity of demand with the midpoint method and see whether demand is elastic, inelastic, or unit elastic.

Decompose any whole number from 2 to 1,000,000,000 into its unique prime factors in exponent form — for example 360 into 2^3 multiplied by 3^2 multiplied by 5.

Calculate the maximum height of a projectile (h = v²·sin²θ / 2g) from its initial velocity and launch angle, ignoring air resistance.

Calculate the horizontal range of a projectile on level ground (R = v² × sin(2θ) / g) from its launch speed and angle, ignoring air resistance.

Calculate the time of flight, horizontal range, and maximum height of a projectile launched from ground level — time = 2v·sinθ/g, range = v²·sin(2θ)/g, height = v²·sin²θ/(2g).

Calculate the volume, lateral surface, and total surface area of a square pyramid frustum from its bottom side, top side, and height — volume = (h/3)(a² + ab + b²).

Calculate the total and lateral surface area of a square pyramid from its base edge and slant height — total = b² + 2bl, lateral = 2bl.

Calculate the volume, base area, and slant height of a square pyramid from its base edge and height — volume = (1/3)a²h, base area = a², slant height = √(h²+(a/2)²).

Find the hypotenuse, area, and perimeter of a right triangle from its two legs using the Pythagorean theorem: c = √(a² + b²).

Solve any quadratic equation ax² + bx + c = 0 for its real roots and see the discriminant that tells you how many real solutions exist.

Calculate the area, perimeter, and arc length of a quarter circle from its radius — area = ¼πr², arc length = ½πr, perimeter = ½πr + 2r.

Calculate how much of a radioactive substance is left after decay with N = N0 × (1/2)^(elapsed / half-life), from the initial amount, elapsed years, and half-life.

Solve a proportion A : B = C : D for the missing value and reduce the ratio A : B to its simplest whole-number form.