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Free Wire Gauge Ampacity Calculator

Estimated safe current-carrying capacity by AWG size.

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Inputs

Result

Ampacity (NEC Table 310.16, copper)

20 A

Gauge12 AWG
NoteDerate for bundling, ambient temperature and continuous loads (80%)

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Short answer

Estimated safe current-carrying capacity by AWG size.

What is the Wire Gauge Ampacity Calculator?

Estimated safe current-carrying capacity by AWG size.

How does the Wire Gauge Ampacity Calculator work?

Enter the inputs above and read the result.

Formula

Ampacity from NEC Table 310.16 (copper conductors)

Variables

    Explanation

    Actual safe ampacity depends on insulation type, ambient temperature, and number of current-carrying conductors.

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              Related concepts

              The Wire Gauge Ampacity Calculator sits inside the Everyday & Utility Calculators hub, in the science & electrical cluster. Physics, chemistry and electrical engineering formulas. Understanding the terms below makes the output easier to interpret and easier to compare against neighbouring measures.

              voltagecurrentresistanceampacitymolaritypressure

              Practical use cases and industry applications

              Understanding Wire Gauge Ampacity

              Estimated safe current-carrying capacity by AWG size. Within everyday & utility calculators, wire gauge ampacity belongs to the science & electrical cluster, where it shares terminology and assumptions with closely related tools.

              Learning how wire gauge ampacity is calculated

              Actual safe ampacity depends on insulation type, ambient temperature, and number of current-carrying conductors. Working through the variables one at a time — — makes the result reproducible by hand and easier to sanity-check.

              Using wire gauge ampacity to make a decision

              Because outputs depend on the assumptions you enter, run more than one scenario before committing to a figure.

              How wire gauge ampacity compares with related measures

              voltage, current, resistance, ampacity all describe adjacent aspects of science & electrical. Comparing this calculator's output against those measures — using the related tools listed on this page — prevents a single metric from being read in isolation.

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