Percentage vs AbsoluteVoltage Drop Calculator
Convert volts dropped, percent dropped, and expected load voltage so you can move from specs or field measurements into conductor sizing decisions.
Convert between volts dropped, percent dropped, and expected load voltage. This is useful when a customer, spec sheet, or inspector gives you one form of voltage-drop limit and you need the other before sizing conductors or checking an installed circuit.
Conversion Inputs
Start with source voltage and the drop value you already know
absolute drop = source voltage - load voltage
percentage drop = absolute drop / source voltage x 100
allowable drop in volts = source voltage x target %
Calculated Results
Percent drop, absolute drop, and target comparison
Moderate drop. Often used as a design target for either a feeder or a branch circuit.
A 14.00 V drop on a 480.00 V system is 2.92%. If your design limit is 3.0%, that allows up to 14.40 V of drop and a minimum load voltage of 465.60 V.
Remaining margin: 0.40 V and 0.08%.
Voltage-drop percentages used in design are commonly treated as engineering targets tied to equipment performance, not a substitute for conductor ampacity, overcurrent protection, or local code review.
Use this tool when a spec gives allowable voltage drop as a percentage but field measurements are in volts.
It also works the other direction when an equipment submittal gives a minimum operating voltage and you need to express that as a percentage limit for design.
After conversion, use a conductor-sizing calculator to determine whether the route length, current, and conductor material can actually meet the target.
AC Voltage Drop Calculator
Use conductor impedance and power factor for single-phase and three-phase AC circuits.
DC Voltage Drop Calculator
Check absolute and percentage drop on battery, PV, telecom, and controls circuits.
Wire Size Calculator
Move from a drop target into an actual conductor recommendation.
Wire Tables
Review conductor resistance, ampacity, and reference values before finalizing a design.
NEC Standards
Review code references and informational notes commonly used for voltage-drop design checks.