120 tools

Physics, chemistry and electrical

120 free physics, chemistry and electrical tools, all running in your browser with no sign-up.

Browse all

Velocity calculator: speed, distance and timeFind speed from distance and time, or solve for distance or travel time, with results in m/s, km/h and mph.
Acceleration calculatorWork out acceleration from initial speed, final speed and time, in m/s² and in g, such as a car going from 0 to 100 km/h.
Force calculator: Newton's second law F = maApply Newton's second law: find force from mass and acceleration, mass from force and acceleration, or acceleration from force and mass.
Kinetic energy calculatorCalculate the kinetic energy of a moving object from its mass and speed, in joules and kilojoules, with speed in m/s, km/h or mph.
Gravitational potential energy calculatorCalculate the gravitational potential energy of a raised object from its mass, height and g, with the result in joules and kilojoules.
Work calculator (force × distance)Calculate the work done by a force from its size, the displacement and the angle between them, with the result in joules and kilojoules.
Mechanical power calculatorCalculate power from work and time or from force and speed, in watts, kilowatts, mechanical horsepower and metric horsepower.
Momentum calculatorCalculate the linear momentum of an object from its mass and velocity in kg·m/s, along with the matching kinetic energy.
Impulse calculatorCalculate impulse from force and contact time or from the change in momentum, with the resulting speed change or average force.
Free fall calculatorCalculate how long an object takes to fall from a given height and its impact speed, ignoring air resistance, with an editable g.
Projectile motion calculatorFind the range, maximum height, flight time and impact speed of a projectile from its launch speed, launch angle and starting height.
Centripetal force and circular motion calculatorCalculate centripetal force, centripetal acceleration, angular velocity and period for an object moving in a circle at constant speed.
Friction force calculatorCalculate friction force and normal force for an object on a flat or inclined surface from the friction coefficient, mass and slope angle.
Torque calculatorCalculate torque from force, lever arm length and the angle between them, in N·m with conversions to lbf·ft and kgf·m.
Density calculator: mass and volumeFind density from mass and volume, mass from density and volume, or volume from mass and density, in g/cm³ and kg/m³.
Kinematic equations calculator (SUVAT)Use the constant-acceleration equations to find final velocity, displacement and time from initial velocity and acceleration.
Newton's law of gravitation calculatorCalculate the gravitational pull between two masses from their masses and the distance between their centers using Newton's law and G.
Simple pendulum period calculatorCalculate the period and frequency of a simple pendulum from its length and gravity, plus swings per minute, for small angles.
Hooke's law spring calculatorUse Hooke's law to find spring force, spring constant or extension, along with the elastic energy stored in the spring.
Elastic and inelastic collision calculatorFind the speeds of two bodies after a head-on collision in a straight line, elastic or perfectly inelastic, with momentum and energy lost.
Ohm's law calculatorEnter any two of voltage, current, resistance and power to get the other two instantly using Ohm's law and the power law.
Electrical power calculator (watts)Calculate electrical power in watts and kilowatts from voltage and current for DC, single-phase and three-phase AC, with power factor.
Watts to amps calculatorConvert power in watts to current in amps from the voltage and supply type: DC, single-phase or three-phase AC, with power factor.
kVA to amps calculatorFind the full-load current in amps from apparent power in kVA and voltage, for a single-phase or three-phase generator or transformer.
Resistor color code calculator (4 band)Pick the four band colors on a resistor to read its value in ohms, its tolerance and the lowest and highest value, per IEC 60062.
Resistor color code calculator (5 band)Read a precision 5-band resistor: three digits, then the multiplier, then the tolerance, with the lowest and highest value per IEC 60062.
Resistor value to color codeType a resistance in ohms to get the band colors printed on it in the 4-band or 5-band system, with the tolerance band you choose.
Series and parallel resistor calculatorCombine any number of resistors in series or parallel and get the equivalent resistance at once. Accepts values such as 4.7k and 1M.
Series and parallel capacitor calculatorWork out the equivalent capacitance of any number of capacitors in series or parallel, in pF, nF, µF or mF.
Voltage divider calculatorCalculate the output voltage of a two-resistor voltage divider, with the current through it and the power it wastes, for sensor and microcontroller circuits.
LED resistor calculatorFind the resistor value needed to drive one LED or several in series from your supply voltage, with the nearest standard E24 value and its power.
Cable voltage drop calculatorCalculate voltage drop in a copper or aluminium cable from length, cross-section and current, in volts and percent, for DC, single-phase and three-phase.
Wire size calculator by voltage dropFind the smallest cable cross-section in mm² that meets your voltage-drop limit, then the next IEC 60228 standard size and its actual drop.
Battery life calculatorEstimate how many hours a battery lasts from its mAh capacity and the device current draw, with the usable share of capacity.
Inverter and UPS battery backup calculatorEstimate how long inverter or UPS batteries can run a load in watts, from voltage, amp-hours, battery count, inverter efficiency and depth of discharge.
RC time constant calculatorCalculate the time constant τ of a resistor-capacitor circuit and the near-full charge time 5τ, with a table of charge level at each multiple of τ.
RC filter cutoff frequency calculatorCalculate the −3 dB cutoff frequency of a passive RC low-pass or high-pass filter from its resistor and capacitor, in hertz and angular frequency.
kWh calculator (watts to kWh)Turn a device’s wattage and hours of use into energy in kWh per day and over any period, with the cost at your own price per kWh.
Power factor correction calculator (kvar)Calculate the capacitor kvar needed to raise power factor from its present value to a target, with apparent power before and after.
LC resonant frequency calculatorCalculate the resonant frequency of an LC tank circuit from inductance and capacitance, in hertz and in a short kHz or MHz form.
Molar mass calculatorFind the molar mass of any compound from its chemical formula, with a per-element breakdown and mass percent. Handles brackets and hydrates.
Grams to moles calculatorConvert a mass in grams to moles straight from the chemical formula, and see the molar mass and the number of molecules or formula units.
Moles to grams calculatorWork out the mass in grams of any substance from its amount in moles and its chemical formula, handy for weighing reagents in the lab.
Moles to molecules calculatorTurn an amount in moles into the number of molecules, atoms or ions using the exact Avogadro constant, shown in scientific notation.
Molarity calculatorCalculate the molarity of a solution in mol/L from the solute mass, its formula and the solution volume, plus moles and mmol/L.
Solution preparation calculatorFind how many grams of solute to weigh to make a solution of a set molarity and volume, straight from the formula, with the moles needed.
Dilution calculator (C1V1 = C2V2)Solve the dilution equation C1V1 = C2V2 for stock volume, final concentration or final volume, with the dilution factor and solvent to add.
pH calculator from H+ concentrationCalculate pH from the hydrogen ion concentration, with pOH, the hydroxide concentration and whether the solution is acidic, basic or neutral.
pOH calculator from OH- concentrationCalculate pOH from the hydroxide ion concentration [OH−], then get the pH and hydrogen ion concentration for basic or neutral solutions.
pH to hydrogen ion concentrationConvert a pH value into the hydrogen ion concentration [H+] and hydroxide concentration [OH−] in mol/L, with pOH at 25 °C.
Ideal gas law calculator (PV = nRT)Solve PV = nRT for pressure, volume, moles or temperature of an ideal gas, with units such as kPa, atm, bar, liters and °C.
Percent composition calculatorWork out the mass percent of each element in a compound from its chemical formula, with each element mass and the total molar mass.
Empirical formula calculatorFind the empirical formula of a compound from element mass percents or masses in grams, with a step-by-step table of moles and ratios.
Molecular formula calculatorGet the molecular formula from the empirical formula and the molar mass of a compound, with the multiplier n and the resulting formula mass.
Percent yield calculatorCalculate the percent yield of a chemical reaction from the actual and theoretical yield, with the shortfall, for lab reports and stoichiometry.
Half-life decay calculatorFind how much of a radioactive isotope or a drug remains after a given time from its half-life, with the fraction left and the decay constant.
Solution density calculatorCalculate solution density from solute mass, solvent mass and final volume, plus the solute mass percent and its concentration in g/L.
Molality calculatorCalculate the molality of a solution in mol/kg from the solute mass, its chemical formula and the solvent mass, with the moles of solute.
ppm to molarity calculatorConvert a concentration in ppm (mg/L) for dilute water solutions into molarity in mol/L, mmol/L and µmol/L, using the chemical formula.
Percent to molarity calculatorFind the molarity of a concentrated solution such as 37% HCl or 98% H2SO4 from its mass percent, density and chemical formula.
Wave speed calculator (v = f λ)Find the speed of any wave from its frequency and wavelength, plus the period, angular frequency and wavenumber.
Wavelength to frequency calculator (light)Convert the wavelength of light or any electromagnetic wave to frequency in Hz, GHz and THz using the exact speed of light.
Frequency to wavelength calculatorGet the free-space wavelength of any radio or microwave frequency, with the half-wave and quarter-wave lengths used for antennas.
Photon energy calculatorCalculate photon energy from wavelength in electronvolts and joules, plus frequency and the energy of one mole of photons in kJ.
Doppler effect calculator (sound)Work out the frequency an observer hears when the sound source, the observer or both are moving, with the size of the shift.
Speed of sound in air by temperatureFind the speed of sound in dry air at any temperature in m/s and km/h, plus the time sound takes to travel one kilometer.
Sound intensity level calculator (dB)Convert sound intensity in watts per square meter to a level in decibels relative to the standard threshold of 10⁻¹² W/m².
Sound pressure level (SPL) calculatorConvert sound pressure in pascals to a sound pressure level in dB SPL relative to 20 micropascals, the standard reference in air.
Decibel addition calculatorAdd several sound levels in decibels the correct logarithmic way to get the total level of sources running together, plus the energy average.
Sound level vs distance calculatorFind the sound level at a new distance from a point source using the inverse square law, with the drop or rise in decibels.
Specific heat calculator (Q = mcΔT)Calculate the heat needed to warm a substance, or released when it cools, from mass, specific heat and temperature change.
Latent heat calculator (fusion and vaporization)Calculate the heat needed to melt ice, boil water away or drive any phase change from the mass and the latent heat.
Final temperature of a mixture calculatorFind the equilibrium temperature when two substances are mixed or a hot object goes into cold water, plus the heat transferred.
Heat conduction calculator (Fourier law)Calculate the rate of heat conduction through a wall or slab from thermal conductivity, area, thickness and temperature difference.
Thermal expansion calculator (linear and volume)Calculate how much a rod or pipe grows in length, or a liquid in volume, when temperature changes, from the expansion coefficient.
Snell's law calculator (refraction angle)Find the refraction angle of light between two media from both indices and the incidence angle, with the critical angle and total internal reflection.
Thin lens equation calculatorFind image distance, magnification and image type for a converging or diverging lens from focal length and object distance.
Optical magnification calculatorCalculate lens or mirror magnification from image and object heights, see whether the image is enlarged, reduced, inverted or upright, and get image distance.
Wien's displacement law calculatorFind the wavelength where black-body radiation peaks from its temperature, in nanometers and micrometers, with the photon energy at the peak.
Stefan-Boltzmann law calculatorCalculate the thermal power radiated by a surface from its temperature, area and emissivity, plus net radiation to surroundings at another temperature.
Gear ratio calculatorFind the gear ratio from tooth counts, plus the driven gear speed and output torque from the driver speed and torque.
Pulley speed calculatorWork out the driven pulley speed, the pulley ratio and the belt speed from both pulley diameters and the motor speed.
Lever and mechanical advantage calculatorCalculate the effort needed to lift a load with a lever and its mechanical advantage from the load arm and effort arm lengths.
Simply supported beam deflection, center loadGet the maximum deflection, maximum bending moment and support reactions of a simply supported beam with a point load at midspan.
Simply supported beam deflection, uniform loadCalculate the maximum deflection, bending moment and reactions of a simply supported beam carrying a uniform load over the full span.
Cantilever beam deflection calculatorFind the tip deflection of a cantilever beam and the bending moment at its fixed end for a point load on the free end.
Stress, strain and Young's modulus calculatorCalculate axial stress, strain and Young's modulus from the force, cross-section area, elongation and original length of a sample.
Hydraulic press calculator (Pascal's law)Find the output force on the large piston and the fluid pressure from the force on the small piston and both piston diameters.
Hydraulic cylinder force calculatorCalculate the push and pull force of a hydraulic cylinder from the working pressure in bar, the bore diameter and the rod diameter.
Pipe flow rate calculatorCalculate the flow rate of water or any liquid in a pipe from its inner diameter and flow velocity, in m³/h, L/s, L/min and US GPM.
Reynolds number calculatorCalculate the Reynolds number for flow in a pipe from density, velocity, diameter and viscosity, and see if the flow is laminar or turbulent.
Pump power calculatorWork out the hydraulic power and pump shaft power in kW and hp from flow rate, total head, fluid density and pump efficiency.
Spring constant calculator (Hooke's law)Find a spring's constant from the applied force and how far it stretches or compresses using Hooke's law, plus the stored energy.
Helical compression spring rate calculatorCalculate the rate of a helical compression spring from wire diameter, mean coil diameter, number of active coils and shear modulus.
Bolt torque calculatorEstimate the tightening torque for a bolt from the target preload, the nominal diameter and the nut factor, in N·m and lbf·ft.
Belt length calculatorCalculate the length of an open belt between two pulleys from their diameters and centre distance, plus the wrap angle on the small pulley.
Motor torque calculator from power and speedCalculate motor torque in N·m and lbf·ft from power in kW and rotational speed in rpm, with the power also shown in horsepower.
Shaft torsional stress and twist calculatorCalculate the peak shear stress in a solid round shaft under torque, plus the angle of twist over its length and the polar moment of inertia.
Section moment of inertia calculatorCalculate the second moment of area, section modulus and area of a rectangle, solid circle or round tube for beam calculations.
Euler column buckling calculatorCalculate the critical buckling load of a slender column with the Euler formula from elastic modulus, moment of inertia, length and end fixity.
Escape velocity calculatorWork out the escape velocity from Earth, the Moon, any planet or a custom body of given mass and radius, at any height above the surface.
Orbital period calculator (Kepler's third law)Find how long a planet or satellite takes to orbit the Sun, Earth or another body from its semi-major axis, using Kepler's third law.
Orbital velocity calculatorCalculate the speed and period of a satellite in a circular orbit from its height above Earth, the Moon, Mars or another planet.
Day length calculatorFind how many hours of daylight there are from sunrise to sunset on any date at your latitude, plus night length and daylight with civil twilight.
Weight on other planets calculatorSee how much you would weigh on the Moon, Mars, Jupiter and the other planets, using each body's surface gravity from NASA data.
Light travel time calculatorFind how long light or a radio signal takes to cover any distance in kilometres, miles, astronomical units or light years.
Distance to horizon calculatorWork out how far the horizon is from your eye height above land or sea, and how far away a tall object like a lighthouse can be seen.
Earthquake energy calculatorConvert an earthquake magnitude into the energy released in joules, its TNT equivalent in tonnes and in kilowatt hours.
Earthquake magnitude comparisonCompare two earthquakes to see how many times more energy and ground shaking amplitude one has than the other from the magnitude gap.
Wind chill calculatorFind how cold it feels in wind with the US National Weather Service wind chill formula, in Celsius or Fahrenheit with any wind speed unit.
Heat index calculatorCalculate the heat index from temperature and relative humidity with the NWS Rothfusz regression, plus the heat risk level.
Dew point calculatorCalculate the dew point from air temperature and relative humidity with the Magnus formula, the temperature where water vapour starts to condense.
Relative humidity calculatorCalculate relative humidity from the air temperature and the dew point with the Magnus formula, in Celsius or Fahrenheit.
Absolute humidity calculatorCalculate absolute humidity in grams per cubic metre from temperature and relative humidity, with actual and saturation vapour pressure.
Apparent temperature calculatorCalculate the feels like temperature from air temperature, humidity and wind speed with the Steadman formula used by the Australian Bureau of Meteorology.
Parallax distance calculatorTurn a star's parallax angle in arcseconds or milliarcseconds into its distance in parsecs, light years and astronomical units.
Age on other planets calculatorWork out your age in Mercury, Venus, Mars, Jupiter and other planet years from your birth date and each planet's orbital period.
Lightning distance calculatorWork out how far away a storm is from the seconds between the lightning flash and the thunder, with the speed of sound for the air temperature.
Cloud base height calculatorEstimate the height of the cumulus cloud base above ground from the gap between temperature and dew point, in metres and feet.
Moon phase calculatorFind the Moon's phase, age and illuminated share on any date, plus the next new moon and full moon from the mean lunar month.