Physics Unit Converters for Science and Engineering

Convert units used in mechanics, electricity, magnetism, heat, light, and other areas of physics. These calculators help students check homework, researchers compare measurements, and engineers work with specifications in different unit systems. Use the Force, Energy, and Pressure calculators for common quantities, or choose specialized tools such as the Viscosity Converter, Magnetic Flux Density, Heat Transfer, and Electrical Resistivity calculators. Whether you are working through a physics problem or reviewing technical data, find the quantity you need in the list below.

Viscosity Converter

Convert between dynamic viscosity units (Pa·s, mPa·s, Poise, cP) and kinematic viscosity units (m²/s, mm²/s, Stokes, cSt). Enter a value, pick a unit, and add the density to switch between the two families.

mAh to Wh

Convert a battery's capacity from mAh (or Ah) to watt-hours by entering the charge rating and the nominal voltage. Useful for comparing batteries, estimating runtime, and checking airline lithium-battery limits.

Pressure Altitude

Enter a barometric pressure reading and a reference (sea-level) pressure to find the corresponding pressure altitude in feet, metres, and flight levels, based on the international standard atmosphere.

Henry’s Law

Convert a Henry’s law constant between mol/(L·atm), atm·L/mol, mol/(m³·Pa), mole-fraction forms, atm·m³/mol and cm³/cm³. Enter the value, pick the From and To units, and add a temperature when cm³/cm³ is involved.

Electrical Resistivity

Convert electrical resistivity between Ω·m, Ω·cm, μΩ·cm, Ω·mm²/m, and statΩ·cm. Enter a resistivity value, then select the units to convert from and to.

Calorific Value

Convert a calorific value between MJ/kg, kcal/kg, BTU/lb, and kJ/kg by entering a value and choosing the source and target units. Note: the calculator currently reverses conversions between different units.

Sound

Convert sound pressure levels between dB SPL, Pa, and µPa, or sound intensity between dB IL and W/m². Enter a Sound value and choose the From unit and To unit.

Beaufort Wind Scale

Convert any wind speed (m/s, km/h, mph or knots) to its Beaufort force number and description, or enter a force from 0 to 12 to see the matching speed range.

Pressure

Convert a pressure value between Pa, kPa, MPa, bar, atm, mmHg, cmHg, inHg, psi, and torr. Enter the value and select the starting and target units.

Air Density

Calculate the density of air in kg/m³, lb/ft³ and other units from temperature, pressure and relative humidity. Enter the values and get partial pressures, molar mass and virtual temperature too.

Power Units

Convert power values between watts, kilowatts, megawatts, milliwatts, horsepower (hp and PS), BTU per hour, foot-pounds per second, and kilocalories per hour. Enter a value, pick the units, and get an instant result.

Insulation R-Value

Convert insulation R-values between US imperial units (ft²·°F·h/BTU) and SI metric units (m²·K/W), and get the corresponding U-values in both systems. Just pick the unit system and enter the R-value.

Magnetic Flux Density

Convert magnetic flux density between tesla, millitesla, microtesla, nanotesla, gauss, and kilogauss. Enter a value, then choose the From unit and To unit.

Luminous Intensity

Convert luminous intensity between candela, millicandela, spherical candela, Hefner candle, and Violle. Enter a value and select the units to convert from and to.

Radiation Absorbed Dose

Convert an absorbed radiation dose between grays, milligrays, micrograys, rads, and millirads. Enter a value and choose the units to convert from and to.

Thermal Expansion

Convert a coefficient of linear thermal expansion between 1/°C, 1/K, µm/m·°C, and in/in·°F. Enter a value and select the From unit and To unit. Note: the current calculator gives incorrect results for some unit pairs.

Electric Field

Convert electric field strength between V/m, kV/m, N/C, V/cm, and statV/cm. Enter a value, then choose the From unit and To unit.

Heat Transfer

Convert a heat transfer rate between watts, kilowatts, megawatts, calories per second, and BTU-based units. Enter a rate, then select the From unit and To unit.

Inductance

Convert inductance between henries, millihenries, microhenries, nanohenries, abhenries, and stathenries. Enter a value, then choose the units to convert from and to.

Permeability

Convert a magnetic permeability value between H/m, N/A², G·cm/Oe, and μ₀ using the calculator’s stated factors. Enter a value, then choose the From unit and To unit; see the notes below before using the μ₀ or G·cm/Oe results.

Wind Chill

Enter the air temperature and wind speed to find the wind chill temperature — how cold it really feels on exposed skin — plus a frostbite risk estimate. Supports °C/°F and km/h, mph or m/s.

Electrical Capacitance

Convert capacitance between farads, millifarads, microfarads, nanofarads, picofarads, statfarads, and abfarads. Enter a value, then select the From unit and To unit.

Resistance Units

Convert electrical resistance between milliohms (mΩ), ohms (Ω), kilohms (kΩ), megohms (MΩ) and gigohms (GΩ). Enter a value, pick the source and target units, and get an instant, step-by-step conversion.

Angular Velocity

Convert angular velocity between RPM, rad/s, deg/s, rad/min and more. Enter a value in any unit and instantly get the equivalent in all other common angular speed units.

Conductance Units

Convert electrical conductance between siemens, millisiemens, microsiemens, and nanosiemens. Enter a value, then choose the From unit and To unit.

Frequency

Convert a frequency between Hz, kHz, MHz, GHz, THz, rpm, rad/s, and deg/s. Enter a Frequency value, then choose the From unit and To unit.

Heat Index

Enter air temperature (°F or °C) and relative humidity to find the heat index — how hot it actually feels — with the matching NWS heat risk level.

Mass Flow Rate

Convert a mass flow rate between kg/s, g/s, kg/min, kg/h, lb/s, lb/min, lb/h, and metric tons per hour. Enter a value and choose the units to convert from and to.

Radiation Exposure

Convert radiation exposure between C/kg, mC/kg, μC/kg, and roentgens (R). Enter an exposure value, then select the units to convert from and to.

Dew Point

Enter the air temperature and relative humidity to find the dew point — the temperature at which moisture starts to condense. Results include dew point in °C, °F and K, vapour pressures and a condensation risk assessment.

Magnetic Flux

Convert magnetic flux between webers, milliwebers, microwebers, nanowebers, and maxwells. Enter a value, then choose the From unit and To unit.

Magnetomotive Force

Convert magnetomotive force between ampere-turns, kiloampere-turns, milliampere-turns, and gilberts. Enter an MMF value, then choose the units to convert from and to.

Radioactivity

Convert radioactive activity between Bq, kBq, MBq, GBq, Ci, mCi, and µCi. Enter an activity value, then choose the starting and target units.

Light Luminance

Convert luminance between cd/m², nits, foot-lamberts, stilbs, and other units. Enter a luminance value, then choose the From unit and To unit.

Linear Acceleration

Convert linear acceleration between m/s², cm/s², ft/s², in/s², Gal, and standard gravity (g). Enter a value, then choose the units to convert from and to.

Lumens to Watts

Estimate a light source’s power consumption from its brightness in lumens. Enter the luminous flux and select a luminous efficacy to convert lumens to watts.

Moment of Inertia

Convert a moment of inertia between kg·m², g·cm², lb·ft², lb·in², and oz·in². Enter a value, then choose the From unit and To unit.

Electric Charge

Convert electric charge between coulombs, millicoulombs, microcoulombs, nanocoulombs, and ampere-hours. Enter a value, then select the From unit and To unit.

Electric Current

Convert electric field strength between V/m, kV/m, N/C, V/cm, and statV/cm. Enter an electric field value, then select the units to convert from and to.

Surface Tension

Convert surface tension between N/m, dyne/cm, mN/m, and kg/s². Enter a value, then choose the units to convert from and to.

Torque

Convert torque between N·m, kN·m, N·cm, kgf·m, lbf·ft, and lbf·in. Enter a torque value, then choose the units to convert from and to.

Molar Flow Rate

Convert a molar flow rate between mol/s, mmol/s, mol/min, mol/h, kmol/h, and mol/day. Enter a value, then select the starting and target units.

Specific Heat

Convert specific heat capacity between J/g·°C, J/kg·K, kJ/kg·K, cal/g·°C, and BTU/lb·°F. Enter a value and choose the From unit and To unit.

Acceleration Units

Convert an acceleration value between m/s², ft/s², standard gravity (g), and Gal. Enter the value, then choose the From unit and To unit.

Density Converter

Convert density values between kg/m³, g/cm³, g/mL, lb/ft³, lb/in³ and more. Enter a value, pick a unit, and get the equivalent density in all common units at once.

Thermal Conductivity

Convert thermal conductivity between W/m·K, kW/m·K, W/cm·K, cal/s·cm·K, and BTU-based units. Enter a value, then choose the From unit and To unit.

Energy

Convert an energy value between joules, calories, kilowatt-hours, BTUs, and other units. Enter a value, then choose the From unit and To unit.

Mass Flux Density

Convert mass flux density between kg/m²·s, g/cm²·s, kg/m²·h, lb/ft²·s, and lb/ft²·h. Enter a value, then choose the units to convert from and to.

Note Frequency

Convert any musical note (C0–B9) to its frequency in Hz, or find the nearest note for any frequency, including the detune in cents. Uses equal temperament with an adjustable A4 reference pitch.

Force

Convert a force between newtons, kilonewtons, dynes, pound-force, kilogram-force, ounce-force, gram-force, and kips. Enter a Force value and choose the From unit and To unit.

Surface Charge Density

Convert surface charge density between C/m², µC/m², nC/m², pC/m², and esu/cm². Enter a nonnegative value and select the starting and target units.

Electric Static Potential

Convert electric potential between volts, kilovolts, millivolts, microvolts, and statvolts. Enter a nonnegative value, then choose the units to convert from and to.

Heat Flux Density

Convert heat flux density between W/m², kW/m², cal/s·cm², BTU/h·ft², and BTU/s·ft². Enter a value, then choose the starting and target units.

Light Illumination

Convert light levels between lux, foot-candles, phot, and lumen-based units. Enter an Illumination value, then choose the From unit and To unit.

Linear Current Density

Convert linear current density between A/m, kA/m, A/cm, mA/mm, and µA/µm. Enter a value and select its original and target units.

Surface Current Density

Convert surface current density between A/m, kA/m, mA/m, A/cm, and the listed electrostatic CGS unit. Enter a value and select the units to convert from and to.

Calculators