The 7 Base Units
| Quantity | Symbol | SI | Imperial |
|---|---|---|---|
| Length / Distance | w, x, y, z | meter (m) | foot (ft) |
| Mass | m | kilogram (kg) | slug |
| Time | t | second (s) | second (s) |
| Temperature | T | kelvin (K), °C | °F, °R |
| Electric Current | i | ampere (A) | — |
| Amount of Substance | M, χ | mole (mol) | — |
| Luminous Intensity | Iv | candela (cd) | — |
Mechanics — Linear
| Quantity | Symbol | SI Unit | SI Base Units |
|---|---|---|---|
| Length / Displacement | d, l, h, r, s | meter (m) | m |
| Area | A, SA | — | m2 |
| Volume | V | liter (L) | m3 |
| Velocity / Speed | v, s | — | m/s |
| Acceleration | a, g | — | m/s2 |
| Jerk / Jolt | J | — | m/s3 |
| Impulse | I | N·s | kg·m/s |
| Linear Momentum | p | — | kg·m/s |
| Force | F | newton (N) | kg·m/s2 |
| Energy / Work / Heat | E, W, K, Q | joule (J) | kg·m2/s2 |
| Power | P | watt (W) | kg·m2/s3 |
| Surface Tension | T | N/m | kg/s2 |
| Pressure / Stress | P | pascal (Pa) | kg/(m·s2) |
| Density | ρ | — | kg/m3 |
Mechanics — Angular
| Quantity | Symbol | SI Unit | SI Base Units |
|---|---|---|---|
| Wavelength | λ | meter (m) | m |
| Frequency | f, ν | hertz (Hz) | 1/s |
| Period | T | second (s) | s |
| Angular Displacement | θ | radian (rad) | 1 |
| Solid Angle | Ω | steradian (sr) | 1 |
| Angular Velocity | ω | rad/s | 1/s |
| Angular Acceleration | α | rad/s2 | 1/s2 |
| Moment of Inertia | I | kg·m2 | kg·m2 |
| Angular Momentum | J, L | kg·m2·rad/s | kg·m2/s |
| Torque | τ | N·m | kg·m2/s2 |
| Angular Impulse | J | N·m·s | kg·m2/s |
Electromagnetics
| Quantity | Symbol | SI Unit | SI Base Units |
|---|---|---|---|
| Electric Charge | Q, q, e | coulomb (C) | s·A |
| Current Density | J | A/m2 | A/m2 |
| Voltage / EMF | V, ℰ | volt (V) | kg·m2/(s3·A) |
| Electric Field | E | V/m | kg·m/(s3·A) |
| Electric Flux | Φe | V·m | kg·m3/(s3·A) |
| Resistance | R | ohm (Ω) | kg·m2/(s3·A2) |
| Capacitance | C | farad (F) | s4·A2/(kg·m2) |
| Conductance | G | siemens (S) | s3·A2/(kg·m2) |
| Magnetic Flux | ΦB | weber (Wb) | kg·m2/(s2·A) |
| Magnetic Flux Density | B | tesla (T) | kg/(s2·A) |
| Inductance | L | henry (H) | kg·m2/(s2·A2) |
Photometry
| Quantity | Symbol | SI Unit | SI Base Units |
|---|---|---|---|
| Luminous Intensity | Iv | candela (cd) | cd |
| Luminous Flux | Φ | lumen (lm) | cd·sr |
| Illuminance | Ev | lux (lx) | cd/m2 |
SI Prefixes
| Prefix | Symbol | Power | Name |
|---|---|---|---|
| quetta | Q | 1030 | nonillion |
| ronna | R | 1027 | octillion |
| yotta | Y | 1024 | septillion |
| zetta | Z | 1021 | sextillion |
| exa | E | 1018 | quintillion |
| peta | P | 1015 | quadrillion |
| tera | T | 1012 | trillion |
| giga | G | 109 | billion |
| mega | M | 106 | million |
| kilo | k | 103 | thousand |
| hecto | h | 102 | hundred |
| deca | da | 101 | ten |
| — | — | 100 | one |
| deci | d | 10−1 | tenth |
| centi | c | 10−2 | hundredth |
| milli | m | 10−3 | thousandth |
| micro | μ | 10−6 | millionth |
| nano | n | 10−9 | billionth |
| pico | p | 10−12 | trillionth |
| femto | f | 10−15 | quadrillionth |
| atto | a | 10−18 | quintillionth |
| zepto | z | 10−21 | sextillionth |
| yocto | y | 10−24 | septillionth |
| ronto | r | 10−27 | octillionth |
| quecto | q | 10−30 | nonillionth |