All Calculators

Calculate the total surface area, lateral surface area, and base area of a cylinder from its radius and height — total = 2πr² + 2πrh, lateral = 2πrh, base = πr².

Calculate the volume, lateral surface area, and total surface area of a cylinder from its radius and height.

Calculate the volume, cross-sectional area, and wall thickness of a hollow cylinder (pipe or tube) from its outer radius, inner radius, and height — volume = π·h·(R²−r²).

Convert digital storage between bits, bytes, kilobytes, megabytes, gigabytes, terabytes and their binary counterparts — KiB, MiB, GiB, TiB.

Convert data transfer rates between bit/s, kbit/s, Mbit/s, Gbit/s, B/s, kB/s, MB/s, and more — instantly, and see why a 100 Mbit/s line downloads at only 12.5 MB/s.

Convert a power level in dBm to milliwatts and watts instantly — useful for RF, Wi-Fi, cellular, and fibre engineers working with signal strength and transmitter power.

Convert a power level in dBW to watts and dBm instantly — essential for radar, satellite, and broadcast engineers working with transmitter power and link budgets.

Calculate the de Broglie (matter) wavelength λ = h / (m·v) of a moving particle in nanometres and metres from its mass and velocity.

Calculate the radioactive decay constant (λ = ln(2) / t½) and the mean lifetime of an isotope from its half-life.

Calculate the power ratio in decibels (dB = 10 · log₁₀(P₁/P₂)) from a measured power and a reference power.

Calculate voltage gain in decibels from an output and input voltage — gain (dB) = 20·log10(Vout/Vin). +20 dB is ×10 voltage, +6 dB ≈ ×2, and negative dB is attenuation.

Combine two sound pressure levels by incoherent addition and get the total level in decibels: 10 × log10(10^(L1/10) + 10^(L2/10)).

Turn a decimal into its simplest fraction, or a fraction into a decimal, in either direction.

Calculate density from mass and volume — density = mass ÷ volume, in kilograms per cubic metre (kg/m³).

Calculate the dew point in °C from the air temperature and relative humidity using the Magnus formula — the temperature at which air saturates and dew forms.

Work out how much concentrate and water to mix for a given dilution ratio like 1:10, for any target volume.

Calculate the final price after a discount and the amount you save from an original price and a discount percentage.

Calculate the straight-line (Euclidean) distance between two points (x1, y1) and (x2, y2) — distance = √((x2−x1)² + (y2−y1)²) — plus the horizontal and vertical legs.

Calculate the straight-line (Euclidean) distance between two points (x1, y1, z1) and (x2, y2, z2) in space — distance = √((x2−x1)² + (y2−y1)² + (z2−z1)²) — plus the three axis legs.

Calculate the perpendicular distance from a point (x0, y0) to a line a·x + b·y + c = 0 in 2D using d = |a·x0 + b·y0 + c| / √(a² + b²).

Find how many positive divisors a number has and what they add up to — useful for number theory, identifying prime numbers, and checking whether a number is perfect or abundant.

Calculate the observed frequency for a moving sound source and a stationary observer — f′ = fv / (v − vₛ) when it approaches, f′ = fv / (v + vₛ) when it recedes — from the source frequency, speed of sound, source speed, and direction.

Calculate the dot product (scalar product) of two 3D vectors: A·B = ax·bx + ay·by + az·bz.

Calculate the doubling time (t = ln(2) / r) of anything growing at a constant rate, plus the quick rule-of-70 estimate, from a single growth rate.

Calculate the aerodynamic drag force (F_d = ½·ρ·v²·C_d·A) in newtons from the fluid density, velocity, drag coefficient, and cross-sectional area.

Calculate efficiency from useful output and total input — efficiency = (output ÷ input) × 100, as a percentage (%).

Calculate the electric charge (Q = I × t) in coulombs from the current and how long it flows, plus the equivalent number of electrons.

Calculate the uniform electric field strength (E = V / d) in volts per metre between two parallel plates from the voltage and their separation.

Work out what an appliance costs to run per day, month, and year from its wattage, daily run time, and your price per kilowatt-hour.

Calculate the area and circumference of an ellipse from its two semi-axes — area = πab, with Ramanujan's accurate perimeter approximation.

Calculate the eccentricity and foci of an ellipse from its semi-major and semi-minor axes — c = √(a²−b²), e = c/a. e = 0 is a circle and e → 1 is highly elongated.

Calculate the perimeter (circumference) of an ellipse from its two semi-axes using Ramanujan's highly accurate approximation.

Calculate the volume of an ellipsoid from its three semi-axes — volume = (4/3)·π·a·b·c. A sphere is the special case where a = b = c.

Convert energy between joule, kilojoule, megajoule, calorie, kilocalorie, watt-hour, kilowatt-hour, BTU, and foot-pound — instantly and with exact, joule-based conversion factors.

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!.

Calculate the error quotient and grade points for language exams.

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.