Amp to Wire Size Calculator

The amp to wire size calculator will help you determine the appropriate electrical wire for your new connection. Keep reading to find out how to size your cables.

The following information is required before we start:

• The amperage at which your system will run: It can be direct current or alternate current (single-phase or three phases).
• System configuration: Single-phase / Three-phase.
• The system voltage.
• Wire size material since it affects the electrical resistivity.
• Distance between your energy source and the equipment you want to energize.
• Allowed voltage drop per the equipment requirements.

Once we have it all, we will use the following formula:

where:

• $\%\text{drop}$ — Allowable voltage drop, in %.
• $V$ — Source voltage, measured in volts.
• $I$ — System current, measured in amperes.
• $\varrho$ — Resistivity of the conductor material, measured in ohmmeters;
• $L$ — Length of the wire, measured in meters; and
• $\phi$ — Phase factor, 1 for DC / AC single phase and $\sqrt{3}/2$ for AC three-phase.
• $A$ — Cross-sectional wire area measured in square meters.

The result will be expressed in mm² (if using the metric system).

It is common for wires to indicate their size in AWG (American Wire Gauge) units. Do not worry; our Amp to wire size calculator also provides results in AWG.

To find the desired wire size:

1. Verify your connection: DC or AC single/three-phase.
2. Specify the voltage source and define the system amperage.
3. Define the wire material you will use, the operating temperature, and the voltage drop.
4. Finally, input the length of your cable (remember, it's a one-way distance).

As a result, the amp to wire size calculator will indicate the cross area of the cable you need to install.

Since you already know how to size a wire based on the required amperes in the system, you can take a look at other calculators:

• Wire size calculator;
• 220 volt wire size;
• DC wire size;
• 12 volt wire size;
• 100 amp wire size; and
• 24 volt wire size.