Voltage Drop Calculator

Calculate voltage drop across your cable runs. Accounts for conductor material, temperature, and cable size.

Circuit Parameters

Source Voltage

Current

One-Way Distance

Ambient Temperature35°C

-10°C15°C25°C45°C60°C

Circuit Type

Conductor

Cable Size

mm²

Voltage Drop

0.32

V (2.7%)

Voltage at Load

11.68

Power Loss

9.7

W (2.7%)

Enter a custom cable size

Size	V-Drop	Drop %	V at Load	Power Loss	Ampacity	Status
1.0 mm²	3.23 V	26.9%	8.77 V	96.8 W	30A > 10A	Over Ampacity
1.5 mm²	2.15 V	17.9%	9.85 V	64.5 W	30A > 15A	Over Ampacity
2.5 mm²	1.29 V	10.8%	10.71 V	38.7 W	30A > 20A	Over Ampacity
4.0 mm²	0.81 V	6.7%	11.19 V	24.2 W	30A	Too High
6.0 mm²	0.54 V	4.5%	11.46 V	16.1 W	40A	OK
10 mm²	0.32 V	2.7%	11.68 V	9.7 W	55A	Good
16 mm²	0.20 V	1.7%	11.80 V	6.0 W	73A	Good
25 mm²	0.13 V	1.1%	11.87 V	3.9 W	100A	Good
35 mm²	0.09 V	0.8%	11.91 V	2.8 W	125A	Good
50 mm²	0.06 V	0.5%	11.94 V	1.9 W	170A	Good
70 mm²	0.05 V	0.4%	11.95 V	1.4 W	210A	Good
95 mm²	0.03 V	0.3%	11.97 V	1.0 W	260A	Good
120 mm²	0.03 V	0.2%	11.97 V	0.8 W	300A	Good

Good = ≤3% drop. Acceptable = 3-5%. Poor = >5%. Based on Copper conductor at 35°C.