All Calculators

Calculate the specific impulse (Isp) of a rocket engine in seconds from its thrust and propellant mass flow rate.

Calculate the specific weight (weight density, γ = ρ·g) of a material in N/m³ from its density and the local gravitational acceleration.

Convert speed between metric, imperial, and nautical units — metres per second, kilometres per hour, miles per hour, feet per second, and knots.

Calculate average speed in km/h and pace in minutes per kilometre from a distance in kilometres and a time in hours.

Calculate the speed of sound in dry air from the air temperature — v = 331.3 + 0.606 × T (T in °C), about 343 m/s at 20 °C.

Calculate the surface area of a sphere from its radius using A = 4 × π × r², plus the volume, in any unit you choose.

Calculate the volume and surface area of a sphere from its radius using V = 4/3 × π × r³ and A = 4 × π × r².

Calculate the curved surface, base radius, and total surface area of a spherical cap from the sphere radius and cap height — curved surface = 2πRh, base radius = √(h(2R−h)).

Calculate the volume, curved surface area, and base radius of a spherical cap from the sphere radius and cap height — volume = (πh²/3)(3R−h), curved surface = 2πRh, base radius = √(h(2R−h)).

Calculate the volume of a spherical sector from the sphere radius and the cap height — volume = (2/3)πR²h.

Calculate the volume of a spherical segment (a zone of a sphere between two parallel planes) from the two base radii and the height — volume = (πh/6)(3a² + 3b² + h²).

Calculate the volume of a spherical wedge (an orange slice) from the sphere radius and the wedge angle in degrees — volume = (2/3)·R³·α, with α in radians.

Calculate the period and frequency of a mass-spring oscillator from its mass and spring constant — period = 2π√(m ÷ k) and frequency = 1 ÷ period.

Calculate the elastic potential energy (PE = ½kx²) in joules stored in a stretched or compressed spring from its spring constant and displacement.

Convert square feet to linear feet, or square metres to running metres. Enter the area and the material width — the width is what makes the conversion possible.

Calculate the total square footage of a rectangular area from its length and width, with the result shown in square feet and square metres.

Calculate the radiated power of an ideal blackbody (P = σAT⁴) in watts from its surface area and absolute temperature using the Stefan-Boltzmann law.

Calculate a vehicle's total stopping distance from its speed, reaction time, and tyre–road friction — stopping distance = reaction distance (v·t) + braking distance (v²/(2·μ·g)).

Calculate the surface gravity (g = G·M/r²) in m/s² of a planet or moon from its mass and radius, plus how many Earth gravities that is.

Calculate the surface (cutting) speed (v = π × d × n) in metres per minute of a rotating part from its diameter and rotational speed.

Calculate the tangential (linear) velocity (v = ω × r) in metres per second of a point on a rotating body from its angular velocity and radius.

Find the capacity of a cylindrical, rectangular, or capsule tank in litres, US gallons, imperial gallons, and cubic metres.

Convert temperature between Celsius, Fahrenheit, and Kelvin — instantly and with exact, offset-based scale definitions.

Calculate the terminal velocity of a falling object, v = √(2mg / ρACd), in metres per second from its mass, area, drag coefficient, and fluid density.

Calculate your test grade as a percentage and a US A–F letter grade from the points you earned out of the total possible points.

Calculate the linear thermal expansion (ΔL = α·L₀·ΔT) of a solid — the change in length and the final length from its expansion coefficient, original length, and temperature change.

Calculate the conductive thermal resistance (R = L ÷ kA) in K/W of a flat layer from its thickness, thermal conductivity, and area.

Calculate the real, apparent, and reactive power of a balanced three-phase AC system from line voltage, line current, and power factor — P = √3 × V_L × I_L × pf.

Calculate the thrust-to-weight ratio (TWR = thrust ÷ (mass × g)) of a rocket, drone, or jet from its thrust and mass — a ratio above 1 means it can lift off.

Calculate torque (τ = F × r) in newton-metres from a force and a lever-arm length, with the force applied perpendicular to the lever arm.

Convert torque between newton-metre, pound-foot, pound-inch, kilogram-force metre, and more — instantly and with exact, newton-metre-based conversion factors.

Convert engine torque (lb-ft) and rpm to power in horsepower and kilowatts — horsepower = (torque × rpm) / 5252, kilowatts = horsepower × 0.7457.

Calculate the efflux speed of fluid leaving an opening below the surface with Torricelli's law — v = √(2gh). The exit speed equals a free fall from the same height and ignores fluid density.

Calculate the surface area and volume of a torus (ring/donut) from its major and minor radius — surface = 4π²Rr, volume = 2π²Rr².

Calculate the volume and surface area of a torus (a donut) from its major radius R and minor radius r — volume = 2π²Rr², surface area = 4π²Rr.

Calculate the secondary voltage of an ideal transformer from its turns ratio — Vs = Vp × (Ns ÷ Np), in volts (V).

Calculate the area of a trapezoid (UK: trapezium) from its two parallel sides and the perpendicular height — area = ((a + b) / 2) × h.

Calculate the area of any triangle from its base and perpendicular height using the formula area = ½ × base × height.

Calculate the total surface area, lateral surface area, and cross-section area of a triangular prism from its three sides and length — uses Heron's formula.

Calculate the volume and cross-sectional area of a right triangular prism from its base, triangle height, and length — volume = ½ × base × height × length.

Work out the price per unit and the price per 100 units from a total price and quantity, so you can compare pack sizes and spot the better-value deal.

Calculate the magnitude (length) of a 3D vector, |v| = √(x² + y² + z²), from its x, y, and z components.

Calculate the output voltage of a two-resistor voltage divider — Vout = Vin × R₂ ÷ (R₁ + R₂), in volts (V).

Calculate the DC voltage drop (Vdrop = 2 × L × I × ρ / A) in volts and the power lost in a wire run from the current, length, resistivity, and cross-section.

Convert volume between metric, US customary, and UK imperial units — millilitres, centilitres, litres, cubic metres, US teaspoons, tablespoons, fluid ounces, cups, pints, quarts, US gallons, and UK gallons.

Calculate the volumetric flow rate (Q = A·v) in cubic metres per second and litres per second of a fluid from its cross-sectional area and velocity.

Convert watts and volts to amps and ohms instantly using Watt's law (I = P ÷ V) — useful for sizing fuses, cables, and circuit breakers for any DC or resistive AC load.

Convert watts to lumens by multiplying wattage by luminous efficacy (lm/W) — compare LED, CFL, halogen, and incandescent bulbs to estimate brightness from power consumption.

Calculate the wavelength and period of an electromagnetic wave from its frequency — wavelength = c ÷ f and period = 1 ÷ f.

Convert weight (mass) between metric and imperial units — milligrams, grams, kilograms, metric tonnes, ounces, pounds, and stone.