Number Density Calculator

A charge carrier is an object which carries electric charge during current flow. The charge carrier type depends on the material's structure in which the charge is transported. For example, there are free electrons in metals, and in semiconductors, there could be both electrons and electron holes.

Every electrical circuit has a resistance (except superconductors) which can be described by Ohm's law. This resistance slows down charge carriers, and therefore they can't reach high speeds. You can check our drift velocity calculator to see how fast charge carriers are.

You can compute charge carrier density with our number density calculator:

where:

• nn – Charge carrier number density;
• ρρ – Density of a material;
• ZZ – Number of free electrons per atom;
• MM – Molar mass (see molarity calculator); and
• NA​NA​ – Avogadro constant NA​=6.0221×1023 mol−1NA​=6.0221×1023 mol−1.

In our number density calculator, you can either choose a specific substance from our examples or enter your parameters.

Remember that the above equation can be applied only to the conductors which have free electrons. If you want to calculate the carrier density in semiconductors, we recommend checking our intrinsic carrier concentration calculator.

Copper is a metal that has high electrical conductivity, and for that reason, many electrical devices rely on copper wiring.

Let's compute the charge carrier density of copper with our number density calculator. We can easily find both the density of a material and the molecular mass of copper (we have provided them as an example substance). Because copper has only one free electron per atom, its charge carrier density is 8.491×1028 carriers/m38.491×1028 carriers/m3. It's tough to imagine how many of them are in one cubic meter. Astonishing number!