Measurement index
Find the measurement you need.
Browse everyday, scientific, digital, astronomical, and historical units by category.
Measurement coverage
Each category groups compatible units and explains where they are commonly used.
103category families1313unit records
Everyday
15 CATEGORIESArea
11 unitsSquare measure for land, surfaces, sections, and sections of material.Volume & capacity
41 unitsLitres, gallons, cubic feet, cooking volumes, and historical capacity.Mass & weight
32 unitsKilograms, pounds, stones, grains, and atomic-scale masses. Mass is kept distinct from force.Temperature
7 unitsKelvin, Celsius, Fahrenheit, Rankine, and historical temperature scales.Time & duration
37 unitsSeconds to millennia, plus sidereal and astronomical durations.Speed & velocity
29 unitsMetres per second, kilometres per hour, miles per hour, knots, and Mach.Acceleration
4 unitsMetres per second squared and gravitational units.Pace
3 unitsTime per distance: minutes per kilometre, minutes per mile.Fuel economy
4 unitsMiles per gallon, litres per 100 km, and reciprocal relationships.Plane angle
32 unitsRadians, degrees, arcminutes, arcseconds, gradians, turns, and compass points.Solid angle
5 unitsSteradians, square degrees, and whole-sphere measures.Cooking measurements
12 unitsCups, spoons, sticks of butter, and ingredient mass-volume context.Oven temperatures
1 unitsGas marks and their Celsius and Fahrenheit equivalents.Typography & screen units
9 unitsPoints, picas, twips, CSS absolute units, and viewport-relative CSS units.Mechanics
12 CATEGORIESForce
32 unitsNewtons, pound-force, dynes, and kips.Torque
5 unitsNewton-metres, foot-pounds, and their context relationship to power.Energy, work & heat
62 unitsJoules, calories, kilowatt-hours, BTUs, and electronvolts.Power
31 unitsWatts, horsepower, BTU per hour, and tons of refrigeration.Pressure & stress
39 unitsPascals, bars, psi, atmospheres, mercury columns, and vacuum measures.Momentum & impulse
3 unitsKilogram-metres per second and its customary equivalents.Moments of inertia
5 unitsMass moment of inertia (kg·m²) and area moment of inertia (m⁴).Angular velocity
2 unitsRadians per second, revolutions per minute, degrees per second.Angular acceleration
2 unitsRadians per second squared and rotation-based rates.Frequency & rotational speed
28 unitsHertz, kilohertz, megahertz, and revolutions per second.Wavenumber
3 unitsReciprocal length in spectroscopic use: inverse metres and kaysers.Spring rate & compliance
29 unitsForce per length and its reciprocal, with reciprocal context.Fluids & heat
19 CATEGORIESVolumetric flow rate
33 unitsLitres per minute, gallons per minute, cubic feet per minute.Mass flow rate
5 unitsKilograms per second and customary mass flows.Viscosity
9 unitsDynamic viscosity (Pa·s, poise) and kinematic viscosity (m²/s, stokes).Surface tension
1 unitsNewtons per metre and dyne-per-centimetre measures.Permeability
2 unitsDarcy-scale permeability of porous materials.Compressibility
2 unitsInverse pressure: per pascal, per bar, per atmosphere.Specific volume
3 unitsCubic metres per kilogram and reciprocals of density.Mass density
30 unitsKilograms per cubic metre, grams per millilitre, pounds per cubic foot.Gas flow
2 unitsStandard-condition gas flows; standard cubic feet per minute require assumed conditions.Leak rate
3 unitsPressure-volume leak rates in torr-litres per second and sccm.Thermal conductivity
6 unitsWatt per metre-kelvin and BTU-based conductivity values.Thermal resistance
4 unitsKelvin per watt for conduction and R-values per unit area.Heat flux & transfer coefficient
4 unitsWatts per square metre and U-values.Heat capacity & entropy
3 unitsJoules per kelvin; entropy shares this dimension.Specific heat & specific entropy
3 unitsJoules per kilogram-kelvin; calories and BTU per mass per degree.Thermal expansion
3 unitsInverse kelvin expansion coefficients and ppm per kelvin.Temperature gradient
2 unitsKelvin per metre and Fahrenheit per foot.Energy density
3 unitsJoules per cubic metre for stored and volumetric energy.Power density
3 unitsWatts per cubic metre for volumetric power.Electricity & light
18 CATEGORIESElectric current
27 unitsAmperes with SI prefixes and cgs electromagnetic units.Electric charge
31 unitsCoulombs, ampere-hours, faradays, and elementary charges.Voltage & electric potential
27 unitsVolts with SI prefixes and cgs statvolt.Resistance & conductance
52 unitsOhms, siemens, and their cgs counterparts.Resistivity & conductivity
5 unitsOhm-metres, siemens per metre, and conductivity in microsiemens.Capacitance
27 unitsFarads with SI prefixes and cgs statfarad.Inductance
26 unitsHenries with SI prefixes.Electromagnetic fields
36 unitsField strengths, flux, flux density, magnetomotive force, and dipole moments.Charge density
3 unitsLinear, surface, and volume electric charge density.Apparent & reactive power
50 unitsVolt-amperes and vars with prefixes.Luminous intensity
26 unitsCandelas and historical candlepower.Luminous flux
1 unitsLumens.Illuminance
27 unitsLux, foot-candles, and phot.Luminance
5 unitsCandelas per square metre, nits, lamberts, and foot-lamberts.Luminous exposure
2 unitsLux-seconds.Radiometry
3 unitsRadiant flux, intensity, irradiance, radiance, and radiant exposure.Optical power
1 unitsDioptres for lens power.Wavelength
3 unitsLight and electromagnetic wavelength with frequency context.Radiation & chemistry
15 CATEGORIESRadioactivity
28 unitsBecquerels, curies, and rutherfords. Not an absorbed dose.Absorbed radiation dose
26 unitsGrays and rads. Energy absorbed per mass; distinct from radioactivity.Equivalent radiation dose
27 unitsSieverts and rems. Biological weighting; never interchangeable with grays or becquerels.Dose rate
3 unitsDose per time: grays and sieverts per hour or second.Radiation exposure
2 unitsIonization exposure in coulombs per kilogram and roentgens.Particle fluence
2 unitsParticles per unit area.Amount of substance
26 unitsMoles and pound-moles.Molar mass
2 unitsKilograms and grams per mole.Molar concentration
6 unitsMoles per litre, molar, millimolar, and gas concentrations.Molal concentration
2 unitsMoles per kilogram of solvent.Mass concentration
4 unitsMilligrams per litre, grams per litre, and solution densities.Mole, mass & volume fractions
5 unitsPercent, per mille, PPM, PPB, and PPT on mole, mass, and volume bases.Catalytic activity
26 unitsKatals and enzyme units.Equivalent concentration
3 unitsNormality and equivalents per litre.pH
1 unitsHydrogen-ion activity scale with logarithmic conversion.Density & materials
5 CATEGORIESLinear density & yarn count
9 unitsTex, denier, and traditional yarn counts.Area density & paper weight
5 unitsGrams per square metre, basis-weight equivalents, and fabric weights.Specific gravity
1 unitsDensity relative to a reference; requires the reference density.Specific weight
26 unitsWeight per volume: newtons per cubic metre.Water hardness
5 unitsCaCO₃ equivalents: milligrams per litre, grains per gallon, and national degrees.Acoustics
3 CATEGORIESDigital & data
3 CATEGORIESNavigation & astronomy
2 CATEGORIESEngineering
8 CATEGORIESPermeance & diffusivity
6 unitsVapour permeance, mass diffusivity, thermal diffusivity, hydraulic conductivity.Specific energy & power
6 unitsEnergy and power per mass: Wh/kg, kJ/kg, power-to-weight ratio.Mach number
1 unitsDimensionless speed ratio requiring the local speed of sound.Reynolds number
2 unitsDimensionless flow regime number.Engine displacement
2 unitsCubic centimetres, litres, and cubic inches of swept volume.Specific fuel consumption
2 unitsMass of fuel per unit energy: g/kWh and lb/(hp·h).Irrigation flow
2 unitsAcre-feet per day and customary irrigation rates.Photography
2 unitsExposure value and its defined illuminance relationship.Historical
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