52 distinct dimensions · 66 categories
Dimension explorer
Every physical quantity reduces to a product of powers of seven base quantities. Two categories with the same reduction are dimensionally identical — which does not make them the same thing, and this page is the quickest way to see where that distinction bites.
The seven base quantities
| Symbol | Quantity | SI base unit |
|---|---|---|
| L | Length | metre (m) |
| M | Mass | kilogram (kg) |
| T | Time | second (s) |
| I | Electric current | ampere (A) |
| Θ | Thermodynamic temperature | kelvin (K) |
| N | Amount of substance | mole (mol) |
| J | Luminous intensity | candela (cd) |
Quantities that share a dimension
These groups reduce to the same formula. Dimensional analysis will not tell them apart, so a check that only balances dimensions can still be wrong.
- 1 — alcohol strength , angle , digital storage , parts & percentages , ratio & decibels
- T⁻¹ — angular velocity , data transfer rate , frequency , radioactivity
- I — electric current , magnetomotive force
- J — luminous flux , luminous intensity
- J L⁻² — illuminance , luminance
- L — length , typography length
- L² T⁻² — absorbed dose , equivalent dose
- M L⁻³ — density , household water hardness
- M L² T⁻² — energy & work , torque