Updated Electrical

Voltage Drop Calculator

Calculate voltage drop, percentage drop, and load voltage for DC, single-phase, three-phase circuits, AWG and mm² cables, plus cable sizing.

DC 1-Phase AC 3-Phase AC Cable Sizing

All-in-One Voltage Drop Suite

Switch between DC, AC, AWG mode, metric mm² mode, and a cable sizing helper based on allowable voltage drop.

Length is one-way from source to load; the calculator uses a return path (2 × length) for DC.

Single-phase AC is treated as a two-wire circuit similar to DC for resistive voltage drop.

Three-phase drop is approximated using ΔV ≈ √3 × I × R × L for a resistive circuit.

AWG sizes are converted internally to approximate mm² area to compute resistive voltage drop.

This mode lets you calculate voltage drop for any system type using metric mm² cables.

The sizing helper estimates the minimum cable cross-section in mm² to stay within the allowed voltage drop.

What Voltage Drop Calculator Calculates

Use Voltage Drop Calculator to calculate voltage drop, percentage drop, and load voltage for DC, single-phase, three-phase circuits, AWG and mm² cables, plus cable sizing.

Related tools in this category are listed under Technology Calculators.

Voltage Drop Calculator Inputs

Voltage Drop Calculator uses System Voltage (V), Load Current (A), One-Way Length, Length Unit, Conductor Material.

Voltage Drop Calculator Formula or Method

  • The tool reads System Voltage (V), Load Current (A), One-Way Length, Length Unit, applies the formula, conversion, lookup, date arithmetic, or conditional rule defined for this calculation, and returns the displayed result. Before comparing Voltage Drop Calculator with another method, confirm that the units and assumptions are equivalent.

Reading Voltage Drop Calculator Results

The results include Voltage Drop, Drop Percentage, Load Voltage, Minimum Size (mm²), Estimated Voltage Drop, Estimated Drop Percentage.

Alongside Voltage Drop Calculator, use Ohm’s Law Calculator to enter any two known values and instantly solve voltage, current, resistance and power.

For a different result from Voltage Drop Calculator, Wattage Calculator can convert volts and amps to watts, estimate appliance energy usage and plan total load and backup capacity for UPS, inverters and generators.

Calculators Related to Voltage Drop Calculator

After checking Voltage Drop Calculator, use Watts To Amps Calculator to convert power in watts to current in amps for DC, single-phase AC and three-phase AC systems. When you need to convert current in amps to power in watts and kilowatts for DC, single-phase AC and three-phase AC systems, use Amps To Watts Calculator. Electricity Calculator covers a separate task: estimate electricity cost, kWh, amps and watts, appliance power usage and monthly electric bills.

After checking Voltage Drop Calculator, use Resistor Calculator to solve Ohm’s Law, combine resistors in series or parallel, decode color bands, calculate tolerance min and max values. When you need to analyze battery capacity, runtime and energy with five tools in one: runtime estimator, series/parallel pack builder, charging time calculator, use Battery Capacity Calculator – Runtime, Pack Builder & UPS. Unit Conversion Calculator covers a separate task: convert length, area, volume, weight, temperature, speed and data units between metric, imperial, US and UK systems in one place.

After checking Voltage Drop Calculator, use Unit Converter to convert between hundreds of units across length, mass, temperature, time, volume, speed, data, pressure, energy, power and more.

Frequently Asked Questions About Voltage Drop Calculator

It is used to calculate voltage drop, percentage drop, and load voltage for DC, single-phase, three-phase circuits, AWG and mm² cables, plus cable sizing.

It uses System Voltage (V), Load Current (A), One-Way Length, Length Unit, Conductor Material.

Voltage Drop Calculator uses The tool reads System Voltage (V), Load Current (A), One-Way Length, Length Unit, applies the formula, conversion, lookup, date arithmetic, or conditional rule defined for this calculation, and returns the displayed result.

It returns Voltage Drop, Drop Percentage, Load Voltage, Minimum Size (mm²), Estimated Voltage Drop, Estimated Drop Percentage.

Check System Voltage (V), Load Current (A), One-Way Length first. Differences can also come from rounding, unit choices, or a different formula or rule set.