Free voltage drop calculator: estimate voltage drop, percent drop, and voltage at the load from system voltage, current, wire length, AWG size, and conductor material.
Electrical notice: This voltage drop calculator uses simplified DC-resistance estimates for copper and aluminum conductors—it is not a substitute for NEC load calculations, power-factor correction, or stamped engineering. Size feeders and branch circuits per applicable code and local authority.
Summary: Enter system voltage, phase, load current, one-way circuit length, AWG size, and conductor material. You get voltage drop (V), percent drop, voltage at load, a pass/fail note, and an AWG scenario table.
Voltage Drop Calculator
Use this voltage drop calculator when sizing branch runs, checking whether a long feed meets the common 3% branch / 5% total guidance, or comparing conductor sizes before you pull wire.
