Southwire's voltage drop calculator will help you determine the proper wire size for an electrical circuit based on the voltage drop and current carrying capacity of an electrical circuit. Determines wire size to meet specific voltage drop limits or calculates voltage drop for a specific conductor run. When sizing conductors, calculations limits wire size to voltage drop and NEC ampacity. Southwire's Voltage Drop Calculator is designed for applications using AWG and KCMIL sizes only.

What’s New

Version 2.1.6

- Removed link to the SIMpull 600V Calculator on the More screen

Ratings and Reviews

4.3 out of 5
420 Ratings

420 Ratings

mchcfamily ,


calculator works as expected.

1MidwestMadMan ,

Choice Between AWG and Metric wire Gauge

Why does this app give a choice of Metric vs. Imperial? When I chose metric in the inputs and go to the next screen for voltage drop calculation there is no option but to use AWG and no option for metric cable size e.g. 2.5, 4, 6, 10, 16, 25, 35, 40, 50, 70, 95, 120, 150, 185, 240, 300, 400 mm2 size conductors. I am currently working British Standard regulations and really though I had something useful with this app for a min. Guess not.

Developer Response ,

We're sorry to hear Southwire's Voltage Drop Calculator did not meet your needs. Metric vs. Imperial refers to the cable length, not the cable size. We understand how that could be confusing, so we're going to make some changes to the app store description and within the app itself to make this easier to discern. Southwire's Voltage Drop Calculator is designed for applications using AWG and KCMIL sizes only.

pacificlp ,

Updated app not so simple

The original app was very easy to use and very simple, after putting in a simple calculation using #8 wire, the numbers just didn't add up. Didn't understand what is meant by "imperial" vs "metric" although I know what metric is


Southwire Company
19.6 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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