Calculate resistive/reactive voltage drop, receiving voltage, percentage drop, and conductor loss from measured cable data.
Trades & Professional Tools · Electrical
Enter your project measurements
Measured inputs · visitor-entered product and design assumptions
1EnterProvide the known values
2CalculateResults update automatically
3VerifyReview the details and units
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Measure using one consistent system. Product coverage, density, resistance, waste, and safety assumptions must come from the actual product data or project specification. Values stay in this browser.
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Calculate resistive/reactive voltage drop, receiving voltage, percentage drop, and conductor loss from measured cable data.
At a glance
See the relationship
Source voltage (line-to-line for three-phase) (V)Load current (A)One-way circuit lengthConductor resistance at operating temperature (Ω/km)
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Voltage Drop resultThe calculator connects the entered electrical values above to the outputs below. Change one input at a time to see which assumption has the greatest effect.
The relationship
The formula used here
DC/single-phase ΔV = 2LI(Rcosφ ± Xsinφ); balanced three-phase ΔV = √3LI(Rcosφ ± Xsinφ), using + for lagging and − for leading load current, Ω/km values, and one-way kilometres.
This relationship is applied to the values you enter. Read all relevant outputs together instead of treating one displayed value as a complete electrical decision.
Field reading
Use the result as a next check
Enter a coherent scenario
Keep phase, voltage basis, units, and operating condition consistent across the entered values.
Read the full result
Use measured or nameplate values from the same operating condition, then read voltage, current, power, and power factor together rather than in isolation.
Keep the boundary clear
It does not approve equipment, conductor or protective-device selection, code compliance, energized work, or electrical safety.
Quick guide
How to use this calculator
Choose the calculation mode or measurement system that matches the values you actually have.
Enter measured project dimensions and use product-specific coverage, density, yield, resistance, or waste data where requested.
Review the intermediate results before ordering material or applying the result on site.
Calculation method
Calculation method
DC/single-phase ΔV = 2LI(Rcosφ ± Xsinφ); balanced three-phase ΔV = √3LI(Rcosφ ± Xsinφ), using + for lagging and − for leading load current, Ω/km values, and one-way kilometres.
The calculator preserves full internal precision and rounds only displayed results. Quantity outputs round up when whole purchasable pieces are required.
Worked example
Worked example
A 20 m, 10 A single-phase run at 0.05 Ω/km and unity PF drops 0.02 V.
DC/single-phase ΔV = 2LI(Rcosφ ± Xsinφ); balanced three-phase ΔV = √3LI(Rcosφ ± Xsinφ), using + for lagging and − for leading load current, Ω/km values, and one-way kilometres.
Supported inputs
Precision and limits
Electrical planning boundary
Electrical results use the measured, nameplate, manufacturer, code-table, test, and correction values you enter. They do not select conductors or protective devices, establish breaking capacity or disconnection time, perform coordination or arc-flash studies, approve energized work, or replace the locally adopted code and a qualified electrical professional.
Planning scope
This calculator supports measurement, estimating, and scenario planning. It does not inspect a site, select a product, certify a design, or replace drawings, specifications, manufacturer instructions, local codes, permits, or a qualified trade professional.
Measured and product-specific inputs
Nominal dimensions can differ from actual dimensions. Verify inside pipe diameters, actual lumber sizes, product coverage, bag yield, material density, conductor resistance, waste, and packaging against the materials used on the project.
Safety and regulatory limits
Electrical, HVAC, structural, excavation, roofing, pressure, lifting, and life-safety work may require jurisdiction-specific calculations and professional approval. Do not use a generic planning result as a code-compliance or safety determination.
Precision and privacy
Inputs accept bounded plain decimals. Calculations remain in this browser and raw entered project values are not submitted to 365CALCS.COM.
