Type
Type
Please enter all required numeric values.
RESULTS
Input Parameters Specification
MaterialSelect conductor material such as copper, aluminium, silver, gold, nichrome, nickel, or graphite.
ResistivityMaterial resistivity in ohm-meter is automatically loaded from the selected material table.
Wire DiameterEnter AWG, inch, or mm wire diameter. AWG supports normal numbers and large sizes like 4/0.
Wire Length One WayEnter one-way cable distance in feet or meters for voltage drop calculation.
Current TypeSelect DC, AC single phase, or AC three phase for the voltage drop multiplier.
Voltage and CurrentSupply voltage and load current are used to calculate voltage drop percent and conductor resistance.
Practical Operational Examples
Electrical Cable Run
Estimate voltage drop for copper or aluminium wiring in DC, single-phase AC, and three-phase AC systems.
Conductor Material Comparison
Compare voltage loss for different wire materials, wire gauge, length, and current in practical cable design.
Diagrams & Theory
Voltage drop happens because every wire has resistance. Higher current, longer cable length, smaller diameter, or higher resistivity material increases voltage drop.
Formulas & Mathematical Logic
Step 1: Material selection fills resistivity ρ from the original material list.
Step 2: Wire diameter is converted from AWG, inch, or mm into meters.
Step 3: If length is entered in feet, length is converted to meters by multiplying by 0.3048.
Step 4: Wire area A = π × d² / 4.
Step 5: Wire resistance R = 2 × ρ × Length / A.
Step 6: Voltage drop Vdrop = Current × R. For three phase, Vdrop is multiplied by 1.732 / 2.
Step 7: Voltage drop percentage = Vdrop / Voltage × 100.
Step-by-Step Example
Example: material = Copper, wire size = 10 AWG, length = 50 feet, current type = DC, voltage = 12 V, current = 20 A.
The calculator loads copper resistivity automatically and converts 10 AWG into wire diameter.
Length is converted from feet to meters when feet is selected.
Wire area is calculated from diameter, then conductor resistance is calculated from resistivity and length.
Finally, voltage drop and voltage drop percentage are displayed in the result cards.
How to Use This Calculator
Select the conductor material so resistivity fills automatically.
Enter wire diameter as AWG, inch, or mm.
Enter one-way wire length and choose feet or meters.
Select DC, AC single phase, or AC three phase.
Enter supply voltage and load current.
Click Calculate to get voltage drop, percentage drop, and resistance.
About This Calculator
Estimate voltage loss across real wire and cable runs.The CalcBoy Wire or Cable Voltage Drop Calculator helps calculate voltage drop, voltage drop percentage, and conductor resistance from material, gauge, length, voltage, and current.
Every wire has resistance, even when it looks like a simple piece of copper or aluminium. When current flows, part of the supply voltage is lost inside the conductor before reaching the load. This voltage drop can make motors start weakly, LEDs dim, inverter lines heat up, audio amplifiers lose headroom, and DC devices behave incorrectly. The effect becomes stronger with long cable runs, high current, small wire diameter, or high-resistivity material.
This calculator is useful for DC wiring, battery cables, solar wiring, automotive electronics, single-phase AC loads, three-phase cable checks, and workshop cable comparison. It supports common conductor materials and accepts wire diameter as AWG, inches, or millimeters, making it practical for both electrical design and repair work.
Best UseVoltage drop checks for DC, single-phase AC, and three-phase cable runs.
Material ChoiceCopper, aluminium, silver, gold, tungsten, platinum, lead, graphite, nichrome, and nickel.
Input FlexibilityEnter wire size as AWG, inch diameter, or mm diameter.
Design ReminderLonger cable and higher current increase voltage drop quickly.
Tip: A low voltage drop percentage is especially important for low-voltage systems like 12 V and 24 V DC, because even a small voltage loss can become a large percentage of the supply.
Frequently Asked Questions
What is voltage drop?
Voltage drop is the voltage lost in a conductor because of wire resistance while current flows through it.
Why does wire length affect voltage drop?
Longer wire has more resistance, so it causes more voltage loss at the same current.
Why does wire diameter matter?
A larger diameter gives more conductor area, reducing resistance and lowering voltage drop.
Can I use AWG values like 4/0?
Yes. The AWG input supports normal gauge numbers and large sizes such as 2/0, 3/0, 4/0, 5/0 and 6/0.
Why is material resistivity important?
Different materials have different resistance per meter. Aluminium, nichrome, graphite, and copper can produce very different voltage drops for the same size and length.
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