Wire Gauge Calculator

Use this wire gauge calculator to compare wire size, resistance or current carrying details. Enter wire length, current, material, gauge and voltage settings and review estimated resistance, voltage drop or suitable wire size.

Recommended gauge
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Voltage drop at that gauge —
Percent drop —

A general guide based on common ampacity and the 3% voltage-drop rule — always follow local electrical code and consult a licensed electrician for actual installations.

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How it works

Recommended gauge sized to keep current within safe ampacity and voltage drop under 3%

How to use the Wire Gauge Calculator

Start by entering wire length, current, material, gauge and voltage settings. Keep the units consistent and check that each value belongs to the same question.

The result gives estimated resistance, voltage drop or suitable wire size. Installation rules, temperature and protection devices affect the final choice. Use it as a guide and check any instructions, rules or professional advice that apply.

Frequently Asked Questions

What does this wire gauge calculator calculate?
It gives estimated resistance, voltage drop or suitable wire size. Installation rules, temperature and protection devices affect the final choice.
What information should I enter?
Enter wire length, current, material, gauge and voltage settings. Use the same units throughout so the result is easier to understand.
Does a thicker wire always solve the problem?
It can reduce resistance, but the complete installation still needs to meet electrical requirements.