Free Science & Engineering Calculators

Calculate acceleration with the formula a = (v − u) / t. Enter the initial velocity, the final velocity, and the time over which the change happens to get the acceleration in metres per second squared (m/s²) instantly.

This battery capacity calculator computes runtime, energy content, or required capacity for any battery-powered device. Enter your battery's mAh rating, nominal voltage, and average current draw to instantly get operating time and watt-hours.

Calculate the buoyancy force acting on any object submerged in a fluid using Archimedes' principle. Enter the fluid density, gravitational acceleration, and submerged volume to instantly find the upward buoyant force.

Find the capacitive reactance of a capacitor at a given frequency using Xc = 1/(2π·f·C). Enter the signal frequency in hertz and the capacitance in microfarads (µF), and the calculator returns the reactance in ohms, in kilohms, and the angular frequency ω = 2πf.

Find the energy stored in a capacitor from its capacitance and voltage using E = ½·C·V². Enter capacitance in microfarads (µF) and voltage in volts to get the stored energy in joules and millijoules, along with the stored charge in coulombs and microcoulombs.

Calculate the inward (centripetal) force and acceleration needed to keep an object of mass m moving at speed v around a circle of radius r, using F = m·v²/r.

This calculator solves all key circular motion quantities — centripetal acceleration, centripetal force, period, frequency, angular velocity, and linear speed — from any combination of inputs you provide.

The combined gas law relates the pressure, volume, and absolute temperature of a fixed amount of gas between two states. It states that the quantity PV/T stays constant when the amount of gas does not change, which is written P1·V1/T1 = P2·V2/T2. Enter any five of the six values (two pressures, two volumes, two temperatures) and this calculator solves for the sixth. Temperatures must be entered on the Kelvin (absolute) scale; a value in Celsius is converted with K = °C + 273.15. Pressure and volume may use any units, provided you use the same unit for both states.

Convert a power or voltage ratio into decibels (dB) instantly. Choose power mode (10·log₁₀) for watts or voltage/amplitude mode (20·log₁₀) for volts, current, or sound pressure, and read the gain or loss live.

Calculate density, mass, or volume from the relation ρ = m / V. Enter any two values and this tool solves the third instantly, showing the answer in both kg/m³ and g/cm³.

This dilution calculator solves the classic dilution equation C₁V₁ = C₂V₂ for any single unknown. Enter any three of the four quantities — initial (stock) concentration C₁, initial volume V₁, final (diluted) concentration C₂ and final volume V₂ — and the calculator finds the missing value, then tells you how much stock to take and how much solvent to add. It is the everyday tool chemists, biologists and lab technicians use to dilute a concentrated stock solution down to a working concentration without re-deriving the algebra each time.

This dynamic pressure calculator finds the kinetic pressure of a moving fluid from its density and speed using the equation q = ½ x ρ x v². Enter the fluid density in kilograms per cubic metre and the velocity in metres per second, and the tool returns the dynamic pressure in both pascals and kilopascals. Dynamic pressure (often written q) is the pressure associated with a fluid's motion, as opposed to its static pressure, and it is fundamental to aerodynamics, wind loading, pitot-tube airspeed measurement, HVAC duct design and any problem where you need to quantify the force a flow exerts on a surface.

Calculate volumetric flow rate from cross-sectional area and fluid velocity using Q = A·v, with instant results in both m³/s and L/s.

This force calculator applies Newton's second law of motion, F = m·a, to relate force (F), mass (m), and acceleration (a). Enter any two of the three quantities and the calculator solves for the missing one, returning force in newtons (N), mass in kilograms (kg), or acceleration in metres per second squared (m/s²). Newton's second law is the cornerstone of classical mechanics: it tells you that the net force on an object equals its mass multiplied by the acceleration that force produces, which is exactly what you need when analysing pushes, pulls, weight, friction, or any everyday motion problem.

Calculate the time, impact velocity, or drop height of an object falling freely from rest under gravity (g = 9.80665 m/s²), with the exact kinematic formulas shown for every result.

Calculate the force of friction with the formula Ff = μ·N. Enter the coefficient of friction (μ) and the normal force (N), and instantly read the friction force in newtons — or leave a field blank to solve for μ or N instead.

This gear ratio calculator finds the ratio between two meshing gears from their tooth counts, then uses it to work out the output shaft speed and the torque multiplication of the gear pair. Enter the number of teeth on the driver (input) gear and the driven (output) gear, and optionally an input speed in RPM, and the calculator returns the gear ratio in reduced 'A : B' form, its decimal value, the output speed and the ideal torque multiplier. Gear ratios are central to almost every mechanical drivetrain — from bicycles, drills and conveyor belts to car gearboxes and clock movements — because they let a designer trade rotational speed for torque (or the reverse) without changing the input power.

Calculate how much of a radioactive (or any exponentially decaying) substance is left after a given time using the half-life decay law N = N₀·(½)^(t/t½).

Calculate the maximum theoretical (Carnot) efficiency of a heat engine from its hot and cold reservoir temperatures in kelvin, using η = 1 − Tc/Th.

Solve Hooke's law F = k·x by entering any two of force, spring constant, or displacement — the calculator finds the third and the elastic potential energy.

This Ideal Gas Law Calculator solves the equation PV = nRT for any one unknown quantity — pressure (P), volume (V), amount of substance (n), or temperature (T) — when you supply the other three. The ideal gas law links the four state variables of a gas through a single proportionality constant, the universal gas constant R, and gives a remarkably good description of real gases at low pressures and moderate-to-high temperatures. Enter your known values in consistent SI units and the calculator rearranges the equation to return the missing one, so you do not have to do the algebra or unit-tracking by hand.

Calculate the inductive reactance Xl of a coil from its frequency and inductance using Xl = 2π·f·L, with the result shown instantly in ohms.

This kinetic energy calculator finds the energy of a moving object from its mass and speed using the equation KE = ½ x m x v². Enter the mass in kilograms and the velocity in metres per second, and the tool returns the kinetic energy in both joules and kilojoules, along with the object's linear momentum (p = m x v). Kinetic energy is the energy an object possesses because of its motion, and it is central to problems in mechanics, vehicle safety, sports physics and engineering whenever you need to know how much work was done to set something moving or how much energy it would release on impact.

Calculate the correct series resistor for an LED from your supply voltage, the LED's forward voltage and your target current — plus the power the resistor must dissipate so you can pick a safe wattage.

This Mechanical Efficiency Calculator computes the ratio of useful output work (or power) to total input work (or power), expressed as a percentage. It applies to any machine — hydraulic jacks, gear trains, electric motors, engines, pulleys, and screws.

Calculate molar concentration (mol/L) from moles and volume, or rearrange the formula to solve for moles or volume when you know the molarity.

Convert between moles, mass, and molar mass using n = mass ÷ molar mass, and instantly see how many atoms or molecules that is via Avogadro's number.

Calculate linear momentum p = m·v from an object's mass and velocity, with an optional impulse (J = F·Δt) section. Results update instantly in SI units (kg·m/s).

This Ohm's Law calculator solves for voltage, current, resistance and power in a simple DC circuit. Enter any two of the three core quantities, voltage (V), current (I) or resistance (R), and the calculator computes the missing value along with the electrical power (P). Ohm's Law is one of the most fundamental relationships in electronics: it describes how voltage, current and resistance interact in a conductor, and it underpins almost every circuit calculation you will encounter when working with batteries, resistors, LEDs, motors and power supplies.

Compute the combined resistance of up to four resistors connected in parallel. Enter any one to four values in ohms (Ω) and get the total parallel resistance instantly, plus the series sum for comparison.

Calculate the percent yield of a chemical reaction by dividing the actual mass you recovered by the theoretical mass and multiplying by 100, giving an instant measure of how efficient your reaction or process was.

This pH calculator converts between pH and the hydrogen ion concentration [H+] of an aqueous solution, and also reports the matching pOH and hydroxide ion concentration [OH-]. Enter EITHER a pH value OR a hydrogen ion concentration in moles per litre (mol/L), and the calculator fills in the other three quantities for you. It uses the defining relationship pH = -log10[H+] together with [H+] = 10^(-pH), and the 25 °C water relationship pOH = 14 - pH, so you can move freely between concentration and the logarithmic pH scale without doing the logs by hand. The pH scale runs roughly from 0 (very acidic) through 7 (neutral) to 14 (very basic), and every whole-number step represents a tenfold change in [H+].

Calculate gravitational potential energy with the formula PE = m·g·h. Enter an object's mass, its height above a reference point, and the acceleration due to gravity to get the stored energy in joules and kilojoules instantly.

Calculate mechanical power in watts and horsepower from either work and time (P = W/t) or force and velocity (P = F·v), with the arithmetic shown.

Calculate electrical power dissipation from any two of voltage, current, and resistance. This tool applies the three forms of Joule's law — P = V·I, P = I²·R, and P = V²/R — to return power in watts and solve for the quantity you didn't enter.

This pressure calculator works out pressure, force or area using the fundamental relationship P = F / A. Enter any two of the three quantities — force in newtons (N), area in square metres (m²), or pressure in pascals (Pa) — and the calculator solves for the missing one, showing the answer in both pascals and kilopascals. Pressure describes how concentrated a force is over a surface: the same force spread over a smaller area produces a higher pressure, which is why a sharp knife cuts more easily than a blunt one and why snowshoes stop you sinking into soft snow.

Calculate the range, maximum height, and time of flight of a projectile launched from flat ground. Enter the initial speed and launch angle and get instant, formula-transparent results using g = 9.80665 m/s².

This RC time constant calculator finds the time constant τ of a resistor–capacitor (RC) circuit from the resistance R and capacitance C using the formula τ = R·C. Enter R in ohms and C in microfarads (µF), and the calculator converts the capacitance to farads, returns τ in both seconds and milliseconds, and reports the 5τ interval that is conventionally treated as a full charge or discharge. The time constant tells you how quickly a capacitor charges through or discharges through a resistor, which governs the timing of RC filters, timer circuits, debounce networks, and sensor sampling.

Pick the color of each band on a 4-band or 5-band resistor and instantly read its resistance in ohms, kilohms, or megohms plus the tolerance and the resulting value range.

Calculate the Reynolds number (Re) from fluid density, velocity, characteristic length, and dynamic viscosity, and instantly classify the flow as laminar, transitional, or turbulent.

A full scientific calculator in your browser — trigonometry, logarithms, exponents, roots, factorials, constants, and memory, with degree, radian, and gradian modes.

Calculate the heat energy needed to change a substance's temperature using the formula Q = mcΔT, given its mass, specific heat capacity, and temperature change.

Use this free calculator to find the elastic potential energy stored in a compressed or stretched spring using Hooke's Law formula PE = ½kx².

Calculate tensile stress (σ = F/A), strain (ε = ΔL/L₀), and Young's modulus (E = σ/ε) from force, cross-sectional area, original length, and elongation — with results in both Pa/MPa and Pa/GPa.

This thermal expansion calculator finds how much a solid object grows or shrinks in length when its temperature changes. Enter the original length L₀, the material's linear expansion coefficient α (for example, steel ≈ 1.2×10⁻⁵ per °C), and the temperature change ΔT, and it returns the change in length ΔL in both metres and millimetres along with the final length. Linear thermal expansion is the everyday reason that bridges have expansion joints, railway tracks need gaps, and metal lids loosen under hot water — almost every solid expands when heated and contracts when cooled, and this tool quantifies that effect exactly.

This torque calculator finds the rotational moment τ produced when a force F acts at a distance r from a pivot, using τ = F × r × sin(θ). Enter the force in newtons (N), the lever arm length in metres (m) and the angle θ between the force and the lever arm in degrees, and the calculator returns the torque in newton-metres (N·m) along with handy conversions. Torque, also called the moment of a force, is what makes things rotate: it is the turning effect behind tightening a bolt, spinning a wheel, swinging a door or balancing a see-saw. The angle matters because only the component of the force perpendicular to the lever arm contributes to turning the object.

Calculate the turns ratio of any transformer and instantly find secondary voltage, current, or the number of winding turns needed for a given design.

Compute the output voltage of a two-resistor voltage divider from your input voltage and resistor values, plus the current flowing through the divider chain in amps and milliamps.

Use the wave equation v = fλ to find wave speed, frequency, or wavelength. Works for any wave type — sound, light, water, or radio waves.

Convert between wavelength and frequency for any wave using the relation c = λ·f. Enter one value and the calculator solves for the other, with an editable wave speed that defaults to the speed of light.

This work calculator computes the mechanical work done by a constant force using the equation W = F·d·cos θ, where force F is in newtons (N), displacement d is in metres (m), and θ is the angle between the force and the direction of motion. Enter the three values and the calculator returns the work done in joules (J), along with the result in kilojoules for larger numbers. In physics, work is the energy transferred to or from an object when a force moves it through a distance — and only the component of the force that lies along the displacement actually does work, which is exactly why the cosine of the angle appears in the formula.