Units & ConstantsUnits & Constants

SI units, prefixes, constants

QUICK CONVERTER

→

0.001

SI UNITS

Lengthm

metre · SI base unit of distance

Masskg

kilogram · SI base unit of mass

Times

second · SI base unit of time

Electric currentA

ampere · SI base unit of current

TemperatureK

kelvin · 0 K is absolute zero

Amount of substancemol

mole · 6.022×10²³ particles

Luminous intensitycd

candela · Brightness of a light source

ForceN

newton · 1 N = 1 kg·m/s²

Energy / work / heatJ

joule · 1 J = 1 N·m

PowerW

watt · 1 W = 1 J/s

PressurePa

pascal · 1 Pa = 1 N/m²

FrequencyHz

hertz · 1 Hz = 1 cycle per second

ChargeC

coulomb · 1 C = 1 A·s

VoltageV

volt · 1 V = 1 J/C

ResistanceΩ

ohm · 1 Ω = 1 V/A

CapacitanceF

farad · 1 F = 1 C/V

Magnetic flux densityT

tesla · 1 T = 1 N/(A·m)

RadioactivityBq

becquerel · 1 decay per second

CONSTANTS

Gravity on Earthg

9.81 m/s²

Weight, falling objects, PE

Speed of lightc

2.998×10⁸ m/s

E = mc², optics, relativity

Gravitational constantG

6.674×10⁻¹¹ N·m²/kg²

Newton's law of gravitation

Planck constanth

6.626×10⁻³⁴ J·s

Photon energy, quantum physics

Elementary chargee

1.602×10⁻¹⁹ C

Electrons, electronvolts

Electron massmₑ

9.109×10⁻³¹ kg

Atomic and particle physics

Proton massmₚ

1.673×10⁻²⁷ kg

Nuclear physics

Avogadro constantNₐ

6.022×10²³ 1/mol

Moles ↔ particles

Gas constantR

8.314 J/mol·K

Ideal gas equation

Boltzmann constantk_B

1.381×10⁻²³ J/K

Kinetic theory, entropy

Coulomb constantk

8.988×10⁹ N·m²/C²

Coulomb's law

Standard atmosphereatm

101 325 Pa

Pressure problems

Speed of sound in airv

343 m/s

Echoes, wave equation (at 20 °C)

Density of waterρ

1000 kg/m³

Floating, liquid pressure

Specific heat of waterc

4180 J/kg·K

Q = mcΔT

PREFIXES

Ttera10¹²
Ggiga10⁹
Mmega10⁶
kkilo10³
hhecto10²
ddeci10⁻¹
ccenti10⁻²
mmilli10⁻³
µmicro10⁻⁶
nnano10⁻⁹
ppico10⁻¹²