Mathematics

Convert any decimal number into engineering notation — a coefficient between 1 and 1000 multiplied by a power of ten that is a multiple of three — with the matching SI prefix.

Calculate the area, height, and perimeter of an equilateral triangle from its side length — area = (√3/4)s², height = (√3/2)s, perimeter = 3s.

Calculate the escape velocity (v = √(2GM / r)) of a celestial body in m/s and km/s from its mass and radius.

Calculate base raised to an exponent (base ^ exponent) — including negative and fractional exponents — with a worked example.

Calculate continuous exponential growth (A = P · e^(r·t)) — the final amount and the total change over time from an initial amount, growth rate, and number of periods.

Calculate the photographic exposure value (EV = log₂(N²/t)) from an aperture f-number and a shutter speed in seconds.

Calculate the f-number (f-stop) of a lens from its focal length and aperture diameter using N = focal length ÷ aperture diameter.

Calculate n! (n factorial) — the product of all positive integers up to n, with 0! = 1 by definition. Supports values from 0! up to 170!.

Find the nth Fibonacci number F(n) with F(0) = 0 and F(1) = 1 — the sequence 0, 1, 1, 2, 3, 5, 8, 13 where each term is the sum of the two before it.

Find out exactly what you need on your final exam to hit your target course grade. Enter your current grade, desired grade, and the final's weight.

Calculate the rotational kinetic energy (E = ½Iω²) stored in a flywheel in joules from its moment of inertia and angular velocity.

Convert foot-candles to lux instantly — enter an illuminance reading in foot-candles (lm/ft²) and get the equivalent in lux (lm/m²), the SI unit used in international lighting standards and photometry.

Convert force between newton, kilonewton, dyne, kilogram-force, pound-force, and more — instantly and with exact, newton-based conversion factors.

Enter two fractions and an operation. You get the answer in lowest terms, as a mixed number and as a decimal.

Calculate the distance an object falls and the velocity it reaches in free fall after a given time, ignoring air resistance — distance = ½ × g × t² and velocity = g × t.

Calculate the freezing point depression (ΔTf = i·Kf·m) of a solution from the van 't Hoff factor, the cryoscopic constant, and the molality.

Convert frequency between hertz, kilohertz, megahertz, gigahertz, terahertz, and rpm — instantly and with exact, hertz-based conversion factors.

Convert a frequency in hertz to its period (T = 1/f) in seconds and angular frequency (2πf) in radians per second.

Calculate the friction force (F = μN) in newtons from the coefficient of friction and the normal force pressing two surfaces together.

Convert fuel economy between L/100km, MPG (US), MPG (UK), and km/L — handling the inverse relationship between fuel consumption and efficiency.

Calculate g-force from an acceleration in m/s² by dividing by standard gravity (g₀ = 9.80665 m/s²) to express it as a multiple of Earth's gravity.

Find the greatest common factor (GCF) and least common multiple (LCM) of two integers using the Euclidean algorithm, with the full working shown.

Calculate the gear ratio (driven ÷ driver teeth) of a gear pair and the resulting output shaft speed in rpm from the input speed.

Calculate the geometric mean (G = √(a · b)) of two positive values and compare it with their arithmetic mean.

Find the nth term and the sum of the first n terms of any geometric sequence from its first term and common ratio.

Convert your exam percentage to the 15-point KMK grading scale used across all German states. Instantly see your Notenpunkte, Schulnote, and how close you are to the next grade.

Calculate the error quotient and grade points for language exams.

Convert German upper school points to decimal grades and back.

Generate a linear or IHK grade scale instantly. Distribute test points to grades 1-6 accurately, toggle half-points, and see the full grade table at a glance.

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 the change in Gibbs free energy (ΔG = ΔH − T·ΔS) in joules per mole from a reaction's enthalpy change, temperature, and entropy change.

Work out how much a glass pane weighs from its length, width, thickness and material. Handy before you lift it, hang it, or ask two people to carry it.

Split a total length into a longer and shorter part in the golden ratio φ ≈ 1.618, so that the longer part divided by the shorter part equals phi.

Calculate your GPA on the 4.0 scale from your course grades and credit hours, with an optional prior GPA to work out your cumulative GPA.

Enter a grade on any of four scales and see it on all of them: US 4.0 GPA, percentage, 10-point CGPA and the German 1-6 grade.

Enter a raw score and pick a curve. You get the curved percentage, the points gained, and what all four common curves would do to the same score.

Calculate the gravitational force (F = G·m₁·m₂/r²) in newtons between two masses from their masses and the distance between their centres.

Calculate the remaining quantity of a decaying substance, N = N₀ × (½)^(t / t½), and the percentage still present from the initial amount, half-life, and elapsed time.

Calculate the harmonic mean (H = 2ab / (a + b)) of two positive values and compare it with their arithmetic mean.

Calculate the great-circle (as-the-crow-flies) distance between two points on Earth from their latitude and longitude — the haversine formula with the mean Earth radius (6371 km), in kilometres and miles.

Calculate the heat capacity C = Q / ΔT in J/K from the heat energy added and the temperature change of a whole object.

Calculate the steady-state rate of conductive heat transfer through a wall or insulation layer with Fourier's law (Q = k·A·ΔT/d), in watts.

Calculate heat energy in joules from mass, specific heat, and temperature change using Q = m × c × ΔT.

Calculate the NWS "feels-like" heat index from air temperature (°F) and relative humidity (%) using the full Rothfusz regression — and see the result in both °F and °C.

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 the pH of a buffer solution with the Henderson-Hasselbalch equation (pH = pKa + log₁₀([A⁻]/[HA])) from the pKa and the base and acid concentrations.

Calculate the area of a triangle from its three side lengths using Heron's formula, plus the perimeter — no height or angles needed.

Calculate the area, perimeter, apothem, and diagonals of a regular hexagon from its side length — area = (3√3/2)s², perimeter = 6s, apothem = (√3/2)s, long diagonal = 2s, short diagonal = √3·s.

Calculate the volume, cross-sectional area, and surface area of a regular hexagonal prism from its side length and length — volume = (3√3/2)·s²·L.