Voltage Drop Calculator

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Calculates the reduction in voltage across a component or length of wire in a circuit.

How To Use

How to use this calculator

Start with your values, or try a preset.

Step 1

Enter Source Voltage (V), Current (A), Wire Length (feet), and Wire Gauge (AWG) in the units shown.

Step 2

Read Wire Resistance (Ohms), Voltage Drop (V), and Percentage Voltage Drop (%) in the results panel. Results update as you change the inputs.

Step 3

Choose a preset to load an example, then adjust the values for your situation.

Worked Examples

See the inputs and their calculated results.

Source Voltage (V): 120; Current (A): 10; Wire Length (feet): 50; Wire Gauge (AWG): 14 AWG

Wire Resistance (Ohms): 0.126 Ohms; Voltage Drop (V): 1.26 V; Percentage Voltage Drop (%): 1.512 %

Source Voltage (V): 120; Current (A): 15; Wire Length (feet): 75; Wire Gauge (AWG): 12 AWG

Wire Resistance (Ohms): 0.1191 Ohms; Voltage Drop (V): 1.7865 V; Percentage Voltage Drop (%): 2.1438 %

Source Voltage (V): 240; Current (A): 5; Wire Length (feet): 100; Wire Gauge (AWG): 10 AWG

Wire Resistance (Ohms): 0.09989 Ohms; Voltage Drop (V): 0.49945 V; Percentage Voltage Drop (%): 1.19868 %

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