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Rojony Khatun Author
Rojony Khatun
CalculatorToolsProjectExpert
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Małgorzata Koperska, MD Steven Wooding
Last updated: October 1, 2025

Line to Phase Voltage Calculator | VLL ↔ VLN Tool

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Line to Phase Voltage Calculator

Convert three-phase line-to-line (V_LL) and line-to-neutral (V_LN) voltages for balanced and phasor cases. Includes formulas, examples (230/400, 480/277), and conversion guidance.

line-to-neutral voltage formula

To convert line (line-to-line) voltage to phase (line-to-neutral) in a balanced three-phase wye system use **VLN = VLL ÷ √3**. Reverse with **VLL = √3 × VLN**. For unbalanced systems, compute phasor subtraction (Vab=Va∠θa − Vb∠θb) and take the magnitude to find the corresponding line voltage.

Formula & Table Summary:

Sample Data Table

Line Voltage (VL)Phase Voltage (VP)
415 V240 V
400 V231 V
208 V120 V

three phase phase voltage tool

The Line-to-Phase Voltage Calculator converts between line-to-line (VLL) and line-to-neutral / phase voltages (VLN) for three-phase systems. For balanced wye systems use the simple relation VLN = VLL/√3 (RMS values); conversely VLL = √3·VLN. For unbalanced or phasor inputs, compute each line voltage via phasor subtraction (e.g., Vab=Va∠θa − Vb∠θb) and take magnitudes. Use RMS consistently for equipment sizing; convert to peak if needed (Vpeak=√2·Vrms). This tool helps electricians, engineers and students quickly check standard utility values (230/400, 277/480), design wye/delta connections, and verify per-phase calculations.

line to phase voltage calculator

ParameterSymbolRelation
Line VoltageVL√3 × VP
Phase VoltageVPVL / √3

Frequently Asked Questions - Line to Phase Voltage Calculator:

What is line-to-phase voltage?

Line-to-phase (line-to-neutral) voltage is the voltage from any line conductor to neutral in a three-phase system (V_LN).

How to convert line-to-line to line-to-neutral?

For a balanced wye: V_LN = V_LL ÷ √3 (use RMS values).

How to convert line-to-neutral to line-to-line?

V_LL = √3 × V_LN (RMS, balanced wye).

What is V_LN for a 400 V system?

V_LN = 400 ÷ √3 ≈ 230.94 V (≈230 V).

What is V_LN for a 480 V system?

V_LN = 480 ÷ √3 ≈ 277.13 V (≈277 V).

Do I use RMS or peak values?

Use RMS values for power and equipment ratings; convert to peak with V_peak = √2 × V_rms when needed.

How to compute unbalanced line voltages?

Use phasor arithmetic: V_ab = V_a∠θa − V_b∠θb; then take magnitude |V_ab| for line voltage.

Does delta connection change formula?

In delta, winding (phase) voltages equal line voltages; there is no V_LN unless a neutral is present via star point.

Why √3 appears in conversion?

√3 arises from the 120° phase geometry of balanced three-phase systems when converting vector (phasor) magnitudes.

When is the simple √3 relation invalid?

When the system is unbalanced, has harmonics, or neutral shift—use phasor/sequence analysis instead of √3 relation.

Rojony Khatun

Rojony Khatun

CalculatorToolsProject

Rojony Khatun is the creator of a free online tools website designed to simplify everyday and engineering-related calculations for students, professionals, and hobbyists. The platform offers a wide variety of basic and advanced calculators across key categories, including Electrical Calculators, Electronic Calculators, and Time & Date Calculators, helping users solve problems quickly and accurately.