Voltage Drop Calculator

Your details

Single phase and DC count the run twice (out and back); three phase uses the √3 factor.
A
The one-way distance from the source to the load.
Used to express the drop as a percentage and to find the voltage left at the load.
V
Choose a standard conductor size, or enter a resistance per metre from a cable datasheet.
mm2 sizes (metric) and AWG/kcmil sizes (North America) are both supported.
Set below 1 for inductive AC loads (motors). 1 ignores reactance. Has no effect on DC.
Per-core AC reactance per metre, used with power factor below 1. Leave 0 for DC or short runs.
Ω/m
Currency
Voltage dropWithin recommended limit (<=3%)
5.517V
Drop as percent of supply2.4%
Voltage at the load224.48V
Total loop impedance0.3448Ω
Power lost in the cable88.3W
2.4% %
Recommended<3Acceptable3-5Excessive5+

The voltage drop is 5.517 V.

  • The conductors lose 5.517 V over the run.
  • Drop scales directly with current and length, double either one and the lost voltage doubles.
  • That is 2.4% of the supply; common practice keeps the total drop under 3 to 5%. A larger wire size lowers resistance per metre.

Next stepIf the percentage is too high, step up the conductor size or shorten the run to cut the resistance.

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