Voltage Drop Calculator

Enter the electrical values below to calculate the result.

Conductor Material Select the wire conductor type. Copper is standard.

Wire Gauge (AWG) AWG copper wire size.

Current (Amps) The electrical current in amperes (A).

One-Way Distance (feet) The one-way routing distance of the cable in feet.

Voltage (Volts) The electrical potential in volts (V).

Current Type & Phase Select whether the system is DC, AC Single-Phase, or AC Three-Phase.

Calculation Formula

V_drop = (Phase Factor × K × I × D) / 1000

NEC standards. Conductor resistivity K: Copper = 12.9, Aluminum = 21.2. Phase Factor: AC 1-Phase = 2, AC 3-Phase = 1.732 (√3).

Calculated Result

0.00 V

Calculated voltage drop in volts.

Calculation Breakdown

DETAILED PARAMETER OVERVIEW

Parameter Value

Calculated Value 0.00 V

ℹ️ About Voltage Drop Calculator

The Voltage Drop Calculator converts Amps/Length/Wire to V Drop instantly and accurately. Whether you're sizing electrical equipment, designing circuits, or checking power requirements, this tool gives you fast, reliable results.

📋 How to Use

Enter the value in Amps/Length/Wire.
Enter any other required values (voltage, power factor, etc.).
Click Calculate to convert to V Drop.
Read the result and use the formula shown for manual verification.

🔢 Formula / Calculation Method

V Drop = (2 × L × I × R) ÷ 1,000

R is resistance per km/mile of wire at the given gauge.

👥 Who Uses It

Electricians
Engineers
Solar installers
Contractors
Building inspectors

📌 Practical Examples

Amps/Length/Wire Input

Enter Amps/Length/Wire value and required parameters.

Result

Instantly see the equivalent V Drop value.

Circuit Sizing

Use the result to size wires, breakers, or equipment.

Verification

Cross-check manual calculations.

⭐ Benefits

⚡

Fast

Instant conversion results

🎯

Accurate

Industry-standard formulas

📱

Mobile

Works on any device

🔢

Formula

See the math behind results

🆓

Free

No cost or login

🌍

Universal

Works for any voltage system

💡 Tips

💡Always enter the correct voltage (120V, 220V, 240V, 480V etc.) for your system.
💡For 3-phase systems, use the 3-phase formula option if available.
💡Power factor is typically 0.8–0.95 — use 0.85 if unsure.
💡Always verify calculated values against local electrical codes (NEC, IEC).

❓ Frequently Asked Questions

How do I convert Amps/Length/Wire to V Drop?

Use the formula: V Drop = (2 × L × I × R) ÷ 1,000

What voltage should I use?

Use your system voltage — 120V or 240V for US residential, 230V for UK/EU.

What is power factor?

Power factor (0–1) represents how efficiently power is used. Use 0.8 as a safe default.

Is the calculator accurate?

Yes, it uses standard electrical engineering formulas.

Is it free?

Yes, completely free.

Should I rely on this for wiring?

Always verify with a licensed electrician before making wiring decisions.

Does it support 3-phase?

Yes, select the 3-phase option if your system uses three-phase power.

What is the difference between kVA and kW?

kW is real power; kVA is apparent power. kW = kVA × Power Factor.

🔗 Related Calculators

🚀 Features

⚡

Instant Results

Calculate in seconds, no waiting

🎯

High Accuracy

Precise results every time

📱

Mobile Friendly

Works on any device or screen size

🔒

Privacy First

No data stored or shared

🌍

Works Worldwide

Available 24/7 from anywhere

🆓

100% Free

Always free, no registration needed

⚠️ Common Mistakes to Avoid

⚠️Using the wrong voltage (120V vs 240V) — this halves or doubles results.
⚠️Ignoring power factor for AC circuits — can cause undersized equipment.
⚠️Confusing single-phase and three-phase formulas.
⚠️Using DC formulas for AC circuits without power factor adjustment.

📖 Glossary

Volt (V)

Unit of electrical potential — the 'pressure' that drives current.

Ampere (A)

Unit of electrical current — the 'flow rate' of electrons.

Watt (W)

Unit of real power — energy per unit time.

kVA

Kilo-Volt-Amperes — unit of apparent power in AC systems.

Power Factor

Ratio of real power to apparent power (0 to 1).

kWh

Kilowatt-hour — unit of energy consumed over time.

📢 Disclaimer

Electrical calculations are provided for reference only. Always consult a licensed electrician and verify against local electrical codes before making wiring or equipment decisions.

About Voltage Drop Calculator

Voltage drop describes how energy is lost as heat along a cable length due to electrical resistance. Sizing branch circuits requires keeping voltage drop below 3% under peak load conditions to maintain appliance performance.