Choosing the right type of wire?

I am going to have a something thats runs on 120vac pulling 1-2amps is there a chart or something for choosing the right gauge of wire?

The wire will run from an inverter in the front of my car(by the battery) to the back (near the taillights).

I need the smallest diameter wire possible.

Answer

There are charts that give properties for different gauges of wires. However, you haven't said what your criterion is so there is no way to give a single answer.

One spec might be how much voltage you are willing to let the wire drop. At your 2A current you can compute a maximum resistance from that. With the Ω/foot from a chart, you can compute the maximum length of each guage of wire your system can tolerate.

Or, your criterion might be maximum temperature rise of the wire. There are charts for temperature rise as a function of current for various wires.

For house wiring there are legal requirements too. These are usually based on temperature rise. Each gauge is specified for the maximum fuse or circuit breaker that must be on that circuit.