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.

Voltage Drop Calculator – DC, AC, AWG & mm² Explained

This Voltage Drop Calculator estimates how much voltage is lost along a cable run based on circuit type, cable length, conductor material, and wire size. It reports the voltage drop in volts, the percentage dropative to the supply, and the approximate load voltage.

DC And Single-Phase Circuits

For DC and single-phase circuits, the calculator treats the circuit as a two-conductor loop (outgoing and return). The total resistance is based on conductor resistivity, length, and cross-sectional area, and the voltage drop is approximated using ΔV = I × R.

Three-Phase Circuits

For three-phase systems, the line-to-line voltage drop is approximated with a resistive model using ΔV ≈ √3 × I × R × L, where R is the resistance per meter and L is the length of the cable run. This gives a practical estimate for many balanced three-phase loads.

AWG, mm² Modes And Cable Sizing

The AWG mode converts American Wire Gauge sizes to an equivalent area in mm² and computes voltage drop from that. The mm² mode works directly with metric cable sizes. The cable sizing helpererses the calculation to estimate the minimum cross-sectional area that keeps the voltage drop below the allowed percentage for the specified load.

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