All Calculators

Convert a height in centimetres to feet and inches with exact international conversion factors.

Calculate the volume, curved surface, and total surface area of a hemisphere from its radius using V = 2/3 × π × r³, A = 2 × π × r², and total = 3 × π × r².

Calculate spring force and elastic potential energy from a spring constant and displacement using Hooke's law — force = k × x and PE = ½ × k × x².

Generate official IHK grading tables instantly. Convert maximum exam points to specific grades 1-6 using the standard 92-81-67-50-30 DIHK percentage key.

Calculate impulse — J = F × Δt — the force applied over a time interval, which equals the change in momentum (N·s = kg·m/s).

Calculate the energy stored in an inductor's magnetic field (E = ½LI²) in joules from its inductance and the current flowing through it.

Calculate the kinetic energy (KE = ½mv²) in joules and the linear momentum of a moving object from its mass and velocity.

Generate a fair grading scale with a custom passing threshold (Knick). Instantly calculate exact point boundaries for German grades 1 to 6.

Add up order processing, production, and transit time to find total lead time, and compute the reorder point from daily demand and safety stock.

Convert length between metric and imperial units — millimetres, centimetres, metres, kilometres, inches, feet, yards, miles, and nautical miles.

Solve the thin-lens equation (1/f = 1/dₒ + 1/dᵢ) for the image distance and magnification from a focal length and object distance.

Generate a linear or IHK grade scale instantly. Distribute test points to grades 1-6 accurately, toggle half-points, and export as a printable table.

Calculate profit margin and markup from a cost and a selling price, with the profit per unit shown alongside.

Calculate the selling price and profit from a cost and a markup percentage, with a clear explanation of how markup differs from margin.

Calculate the rest energy of a mass with Einstein's mass-energy equivalence — energy = mass × c², where c is the speed of light.

Calculate mechanical advantage from load and effort force — MA = load force ÷ effort force.

Find the midpoint of the line segment between two points (x1, y1) and (x2, y2) — midpoint = ((x1 + x2) / 2, (y1 + y2) / 2) — the exact centre halfway between them.

Calculate molarity from moles and volume — molarity = moles ÷ litres of solution, in moles per litre (mol/L, also written M).

Calculate the net force on an object from its mass and acceleration using Newton's second law — force = mass × acceleration (F = m × a).

Calculate your weighted grade average in percent — give each grade a share, all shares should add up to 100%. Dynamically supports 2–8 grades.

Convert German upper school points to decimal grades and back.

Calculate voltage and power from current and resistance using Ohm's law — voltage = I × R and power = I² × R.

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

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

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

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 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 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.

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.

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.

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

Calculate the time constant of an RC circuit — τ = R × C — the time it takes to charge to ~63 % or discharge to ~37 % of the final voltage.

Estimate how long a text takes to read from its word count and your reading speed, shown in minutes and seconds.

Calculate the area, perimeter, and diagonal of a rectangle from its length and width — area = L×W, perimeter = 2(L+W), diagonal = √(L²+W²).

Calculate the volume, surface area, and space diagonal of a rectangular prism (box) from its length, width, and height — volume = l×w×h, surface area = 2(lw+lh+wh), diagonal = √(l²+w²+h²).

Calculate the area, perimeter, and apothem of a regular polygon from its number of sides and side length — area = ½ × perimeter × apothem, apothem = s/(2·tan(π/n)).

Calculate the combined resistance of two resistors in parallel using the product-over-sum rule — Rp = (R1 × R2) ÷ (R1 + R2).

Calculate the total resistance of two resistors in series — they simply add: R = R1 + R2.

Calculate the resonant frequency of an LC circuit from its inductance and capacitance — f = 1 ÷ (2π√(L × C)).