3 Phase Power Calculator

Q: How to calculate 3 phase power?

For balanced three-phase with line-to-line voltage and line current: kW = √3 × V × I × PF ÷ 1000 and kVA = √3 × V × I ÷ 1000. Example: 400 V · 52 A · PF 0.85 ≈ 30.6 kW / 36.0 kVA. Enter the same values in this calculator for an instant check. For √3 derivation see the 3 phase power formula guide.

Q: What is 1 kW in amps on 3-phase?

At 400 V line-to-line: 1 kW ≈ 1.44 A at PF 1.0, or ≈ 1.70 A at PF 0.85. Formula: I = (kW × 1000) ÷ (√3 × V × PF). At 480 V and PF 0.85, 1 kW ≈ 1.42 A. Open the 1 kW preset on this calculator or the kW to amps reference table.

Q: How do I convert kW to amps in 3 phase?

Use I (A) = (kW × 1000) ÷ (√3 × V_L-L × PF) with line-to-line voltage. Example: 10 kW at 400 V and PF 0.85 ≈ 17 A. Shareable preset: 1 kW at 400 V, PF 1.0 ≈ 1.44 A.

Q: Why 1.73 for 3-phase power calculation?

1.73 is √3 rounded (≈ 1.732). Balanced three-phase real power with line-to-line voltage and line current is P = √3 × V_L-L × I × PF. Omitting √3 under-estimates three-phase power by about 73%. See the 3 phase power formula guide for full derivation and examples.

Q: What is the formula for 3-phase power to amps?

I (A) = (kW × 1000) ÷ (√3 × V_L-L × PF), or I = (kVA × 1000) ÷ (√3 × V_L-L). Example: 10 kW at 400 V and PF 0.85 is about 17 A. See the 3 phase power formula guide for worked equations; use this calculator or kVA to amps for quick checks.

Q: How many amps is 7.5 kW 3-phase?

It depends on line-to-line voltage and PF. At 400 V and PF 0.85: I ≈ 7.5×1000 ÷ (√3×400×0.85) ≈ 12.7 A. At 480 V and PF 0.85: ≈ 10.6 A. More worked cases are on the 3 phase power formula guide; enter site V and PF in this calculator to match your bus.

Q: What is 3-phase 240v power?

3-phase 240 V usually means 240 V line-to-line (common on some North American delta / high-leg systems and older plant buses). Balanced kW still uses P = √3 × 240 × I × PF ÷ 1000. Do not confuse with single-phase 240 V (no √3) or 208Y/120 V wye. Math: 3 phase power formula guide; concepts: what is 3 phase power.

Q: What is a 3 phase power calculator?

A 3 phase power calculator computes balanced kW and kVA from line-to-line voltage, line current, and power factor using P = square root of three times V times I times PF. Example: 400 V, 52 A, PF 0.85 is about 30.6 kW. Same tool covers 3 phase electrical calculations and AC power calculation searches.

Q: Is this a 3 phase power calculator?

Yes. Enter line-to-line voltage, line current, and power factor to get balanced kW and kVA using P = √3 × V × I × PF. See the Formula section on this page or the 3 phase power formula guide for worked examples.

Q: What are 3 phase electrical calculations / AC power calculations?

Typical 3 phase electrical calculations convert among kW, kVA, and line amps with P = √3 × V × I × PF and kVA = √3 × V × I ÷ 1000. Enter V, A, and PF in this calculator for an instant screen.

Instant 3 phase power calculator for balanced electrical quantities—kW, kVA, and line amps from line V, line A, and PF (√3). It does not select breakers, conductors, transformers, or motor protection. Advanced analysis of inrush, harmonics, and unbalance needs additional data.

Quick answer: how to calculate 3-phase power

kW = √3 × V_L-L × I × PF ÷ 1000 · kVA = √3 × V_L-L × I ÷ 1000. Screen: 400 V · 52 A · PF 0.85 ≈ 30.6 kW / 36.0 kVA. Enter the same V, A, and PF in the calculator below for an instant check.

Open 400 V · 52 A preset V × I → kW ladder kW → amps table

Need kW → amps instead? At 400 V, PF 0.85, 1 kW ≈ 1.70 A (I = kW×1000 ÷ (√3×V×PF))—see the kW → amps table. Derivation and √3 proofs: 3 phase power formula.

Learn before calculating

Three-phase kW and kVA depend on power factor. For PF meaning, correction, and utility context, start with the Power Systems authority guide.

Power Factor Guide → Power hub featured topic →

Input Parameters

Quick Examples:

System type Matches “single and 3-phase power calculator” SERP—switch here instead of leaving the page.

Calculate from

From amps (→ kW / kVA) From kW (→ amps / kVA)

System Voltage (V) 3φ industrial often 380–480 V L-L; 1φ branches often 120/240 V. Prefer measured nameplate voltage.

Current (A) Typical: Small motor 5-20A, Medium motor 20-100A, Large motor 100-500+ A

Power Factor (PF) Typical: Motors 0.80-0.90, Heaters 1.0, Mixed loads 0.85-0.95

About this calculator

Converts balanced three-phase voltage, line current, and PF into real and apparent power for motor lines and feeders. Need instant kW / kVA / line A? Stay on this calculator. Need √3 derivation, worked formula proofs, or load examples? Use the 3 phase power formula guide, then verify numbers here. New to 3φ concepts? Start with 3-phase power explained; for PLN Indonesia connected-power steps (VA ↔ MCB), see tabel daya listrik PLN 3 phase; for the rest of the kW/kVA/current chain, use the power calculators hub.

If you start from kW or kVA without line current, use kW to kVA first, then kVA to amps for balanced line A; use factory load when sizing from device counts. After you have design amps, screen cable size (ampacity + installation derating on your tables) and voltage drop on long feeders; breaker size ties to continuous vs non-continuous duty per NEC or IEC 60364 practices.

Calculation Results

Balanced three-phase, steady-state line current; does not replace motor inrush, harmonic, or unbalance studies.

Engineering disclaimer

This calculator returns balanced steady-state power quantities only. It does not select protection or equipment. Final design requires the applicable code, OEM data, load behavior, conductor and installation details, available fault current, coordination, harmonics, unbalance, and starting conditions.

Balanced 3φ power — quick √3 reference

Illustrative V × I → kW at PF 0.85 from kW = √3 × V_L-L × I × PF ÷ 1000 (line quantities). Covers common 208 / 400 / 480 V buses—open a row to prefill the calculator.

V × I → kW ladder (PF 0.85)

V_L-L	Line I (A)	Approx. kW	Approx. kVA	Open
208	50	15.3	18.0	Preset
208	100	30.6	36.0	Preset
400	10	5.9	6.9	Preset
400	52	30.6	36.0	Preset
400	100	58.9	69.3	Preset
480	50	35.4	41.6	Preset
480	100	70.7	83.1	Preset

kW to amps (3-phase) — quick reference @ PF 0.85 and PF 1.0

I (A) = (kW × 1000) ÷ (√3 × V_L-L × PF). Covers 1 kw to amps in 3 phase, 10 kw to amps 3 phase, and similar lookups. Use measured PF when commissioning.

kW	V_L-L	PF	Approx. line I (A)	Open
1	400	1.0	1.44	Preset
1	400	0.85	1.70	Preset
5	400	0.85	8.49	Preset
10	400	0.85	17.0	Preset
15	400	0.85	25.5	Preset
25	400	0.85	42.5	Preset
1	480	1.0	1.20	Preset
10	480	0.85	14.2	Preset

Reverse: kW → line current @ PF 0.85 (selected)

Legacy two-column view for common motor-line checks.

kW	V_L-L	Approx. line I (A) @ PF 0.85
10	400	17
37	400	63
50	480	71

Formula proofs & √3 derivation: 3 phase power formula · concepts: what is 3 phase power.

3-Phase Power Formula & Explanation

V_L-L: Line-to-line voltage in volts (measured at the equipment or bus).
I (or I_L): Balanced line current in amperes (RMS), one conductor of the three-phase set.
PF: True power factor is real power divided by apparent power. For sinusoidal voltage and current it equals displacement factor cos φ; with distortion, true PF also includes the distortion effect.
kW / kVA: Real and apparent power; kVAR (reactive) fills the triangle when PF < 1.

Balanced line quantities: kW = √3 × V_L-L × I × PF ÷ 1000 and kVA = √3 × V_L-L × I ÷ 1000 so kW = kVA × PF. Example: 400 V, 10 A, PF 0.85 → about 5.9 kW and 6.9 kVA. The green next-step card points to kVA to amps at your voltage and phase.

Why do you multiply by 1.73 (√3) for three phases?

In a balanced three-phase system, the three line-to-neutral voltages are 120° apart. When you express total three-phase power using line-to-line voltage (V_L-L) and line current (I), geometry gives the factor √3 ≈ 1.732. That is why you see 1.73 in field shorthand: P = √3 × V_L-L × I × PF for real power and S = √3 × V_L-L × I for apparent power (kVA).

Quick check: 400 V line-to-line, 10 A line current, PF 0.85 → kW = 1.732 × 400 × 10 × 0.85 ÷ 1000 ≈ 5.9 kW. Without √3 you would under-estimate three-phase power by about 73%. Single-phase formulas omit √3 because only one phase carries the full voltage reference.

kW vs kVA vs kVAR: kW is real power; kVA is apparent; kVAR is reactive. Conductors and sources must carry kVA; utility and PFC discussions often focus on kVAR when PF lags.

Motor note: running FLA follows the formulas above; locked-rotor, thermal overloads, and branch protection follow NEC 430 and IEC 60034 / IEC 60364 practices (or your local code)—size devices with those rules, not this steady-state line alone. Fault current and selective coordination are outside this page.

Delta / Wye and line ↔ phase current

Balanced three-phase power formulas on this page use line-to-line voltage and line current. Topology still matters when you read nameplates or wire a bank:

Connection	Voltage relation	Current relation	Use in this calculator
Wye (Y / star)	V_L-L = √3 × V_L-N	I_line = I_phase	Enter V_L-L and line A (same as phase A)
Delta (Δ)	V_L-L = V_phase	I_line = √3 × I_phase	Enter V_L-L and line A (not coil current alone)

Line ↔ phase current (balanced): Wye I_L = I_ph; Delta I_L = √3 × I_ph (so I_ph = I_L ÷ √3). Example: Delta load drawing 17 A line at 400 V → phase/coil current ≈ 9.8 A. Keep PF on the line-power formulas above—do not swap V_L-N into the √3 line equation.

Bidirectional workflow: know amps → kW here; know kW → amps via the kW→amps table or kVA to amps / kW to kVA. Then screen cable / wire gauge and voltage drop.

Ampacity: tabulated conductor current must be derated for installation method, ambient, grouping, and harmonics on project tables.
Balanced load assumed; unbalance needs per-phase work.
√3 ≈ 1.732 ties line values to total three-phase power.

More: 3-phase power formula & examples · Power factor formula · kW to kVAR / PF correction · 3-phase power guide · Factory load · kW to kVA · kVA to amps · Cable size · Voltage drop · Power Calculators Hub

Power triangle

kVA² = kW² + kVAR²; with PF known, PF = kW ÷ kVA.

Common bus screens (equipment-oriented)

Typical line-current screens at PF 0.85 for plant / commercial buses. These are energy-balance checks—not breaker or cable selections.

Bus	Example load	Approx. line I	Open
208 V 3φ	15 kW feeder	~49 A	Preset
400 V 3φ	30 kW process	~51 A	Preset
480 V 3φ	75 kW motor line	~106 A	Preset

Why there is no motor breaker table here: horsepower and steady-state current do not determine a universally correct breaker. Protection depends on nameplate, starting method, overload, conductors, fault current, coordination, and the adopted code. Use this page for kW/kVA/current relationships, then complete protection with project-specific inputs.

Need the full explanation?

Power factor ties line current to real kW on three-phase buses. Read the cluster authority guide for correction planning and typical industrial PF values.

Power Factor Guide → Return to Power hub →

Frequently Asked Questions

How to calculate 3 phase power?

For balanced three-phase with line-to-line voltage and line current: kW = √3 × V × I × PF ÷ 1000 and kVA = √3 × V × I ÷ 1000. Example: 400 V · 52 A · PF 0.85 ≈ 30.6 kW / 36.0 kVA. Enter the same values above for an instant result. Need the √3 derivation? See 3 phase power formula.

What is the difference between Delta and Wye for 3-phase current?

Wye: I_line = I_phase and V_L-L = √3 × V_L-N. Delta: V_L-L = V_phase and I_line = √3 × I_phase. This calculator expects line-to-line V and line A—see Delta / Wye table. Example: 17 A line on a Delta load → phase/coil ≈ 9.8 A.

What is 1 kW in amps on 3-phase?

At 400 V line-to-line: 1 kW ≈ 1.44 A at PF 1.0, or ≈ 1.70 A at PF 0.85. Formula: I = (kW × 1000) ÷ (√3 × V × PF). At 480 V and PF 0.85, 1 kW ≈ 1.42 A. Open 1 kW @ 400 V preset or see kW → amps table.

How do I convert kW to amps in 3 phase?

I (A) = (kW × 1000) ÷ (√3 × V_L-L × PF) with line-to-line voltage. Example: 10 kW at 400 V, PF 0.85 ≈ 17 A. For apparent-power workflows, convert kW to kVA first on kW to kVA, then use kVA to amps only when you already know kVA.

Why 1.73 for 3-phase power calculation?

1.73 is √3 rounded (≈ 1.732). Balanced three-phase real power with line-to-line voltage and line current is P = √3 × V × I × PF. Example: 400 V, 10 A, PF 0.85 → about 5.9 kW. Omitting √3 under-estimates three-phase power by about 73%. Full derivation and examples: 3 phase power formula · page note Why multiply by 1.73.

What is the formula for 3-phase power to amps?

I (A) = (kW × 1000) ÷ (√3 × V_L-L × PF), or from apparent power I = (kVA × 1000) ÷ (√3 × V_L-L). Example: 10 kW at 400 V, PF 0.85 ≈ 17 A. Worked equations: 3 phase power formula. Instant check: this calculator or kVA to amps.

How many amps is 7.5 kW 3-phase?

Amps depend on line-to-line voltage and PF. At 400 V, PF 0.85: I ≈ 7.5 × 1000 ÷ (√3 × 400 × 0.85) ≈ 12.7 A. At 480 V, PF 0.85: ≈ 10.6 A. Enter your site V and PF above for an instant check—more worked cases on the 3 phase power formula page. Do not size breakers from a single generic “7.5 kW = X A” table alone.

What is 3-phase 240v power?

3-phase 240 V usually means 240 V line-to-line (seen on some North American delta / high-leg buses and older plant systems). Balanced real power is still P = √3 × 240 × I × PF ÷ 1000. Do not confuse with single-phase 240 V (no √3) or 208Y/120 V wye—confirm meter/nameplate voltage first. Math and examples: 3 phase power formula · concepts: what is 3 phase power.

What is a 3 phase power calculator?

A 3 phase power calculator computes balanced kW and kVA from line-to-line voltage, line current, and power factor using P = √3 × V × I × PF. Example: 400 V, 52 A, PF 0.85 ≈ 30.6 kW. Same tool answers “3 phase electrical calculations” and “3 phase AC power calculation” searches.

Is this a 3 phase power calculator?

Yes. Enter line-to-line voltage, line current, and power factor above for balanced kW and kVA using P = √3 × V × I × PF. Formula details: Formula & Explanation on this page · 3 phase power formula guide.

What are 3 phase electrical calculations / AC power calculations?

Typical 3 phase electrical calculations convert among kW, kVA, and line amps with P = √3 × V × I × PF and kVA = √3 × V × I ÷ 1000. Enter V, A, and PF above for an instant screen—then size cable/breaker separately. Worked equations: 3 phase power formula & examples.

What is the difference between line current and phase current in three-phase systems?

Line current flows in each supply conductor; phase current flows in each winding. In delta, line current equals phase current times √3; in wye (star), line current equals phase current. Field work usually starts from line quantities.

How do I calculate kVA from kW in a three-phase system?

kVA = kW ÷ power factor. Example: 10 kW at PF 0.85 gives about 11.76 kVA. The calculator shows both once V, I, and PF are set.

What power factor should I use for different types of loads?

Resistive loads are near PF 1.0; motors often 0.8–0.9; electronics often 0.9–0.95. For mixed plants use a weighted average or the lowest PF for a conservative envelope; 0.85 is a common placeholder when data is thin.

Can this calculator recommend a breaker rating?

No. Balanced steady-state line current is only one input. Breaker selection also depends on load type, conductor protection, starting/inrush, manufacturer limits, fault current, coordination, installation details, and the applicable code.

Can I use this calculator for single-phase systems?

Yes. Set System type → Single-phase. Real power uses P = V × I × PF (no √3); from kW, I = kW×1000 ÷ (V × PF). Keep three-phase selected when you need √3 and line-to-line volts.

How do I calculate 3-phase current from kilowatts?

I (A) = (kW × 1000) ÷ (√3 × V_L-L × PF). Example: 10 kW at 400 V and PF 0.85 is about 17 A. Always use measured V and PF when commissioning.

What is the difference between kW and kVA in 3-phase systems?

kW is real power; kVA is apparent power. kW = kVA × PF. Size transformers and generators on kVA; utility demand charges often track both kW and PF.

How do I convert horsepower to kilowatts for 3-phase motors?

1 HP ≈ 0.746 kW. Convert HP to kW, then use the three-phase current formula with nameplate PF and efficiency when known; remember locked-rotor and starting multiples are not modeled here.

What voltage should I use for 3-phase calculations?

Use line-to-line (phase-to-phase) voltage. Nominal 380/400/415 V is common in IEC markets; 480 V is common in North America. Prefer measured bus voltage at the equipment terminals when harmonics or long feeders skew the nameplate assumption.

How do I calculate 3-phase power factor from current and voltage?

If kW and kVA are known, PF = kW ÷ kVA. If kW, line-to-line voltage, and line current are known, PF = (kW × 1000) ÷ (√3 × V × I). Example: 10 kW at 400 V with 20 A line current is about 0.72 PF. Very low PF may trigger correction or utility penalties.

Why is my 3-phase current calculation different from measured values?

Mismatch comes from nominal versus measured voltage, true PF versus assumed PF, phase unbalance, harmonics, VFD waveforms, and instrument accuracy. Use clamp-on RMS readings at the load and reconcile with the site energy meter when disputes arise.

What is a 3 phase current calculator?

A 3 phase current calculator solves line amps from kW or kVA with line-to-line voltage (and PF when starting from kW): I = (kW × 1000) ÷ (√3 × V × PF). This page does that path; if you already know kVA, use kVA to amps.

Is 3 phase voltage the same as 3 phase power?

No. 3 phase voltage is the system line-to-line (or line-to-neutral) rating—an input. 3 phase power is kW/kVA from V, I, and PF. Enter your bus voltage here; do not treat “400 V three-phase” alone as a power result.

What is the 3-phase apparent power formula?

S (kVA) = √3 × V_L-L × I ÷ 1000 (balanced). Real power uses the same √3 term with PF: P (kW) = √3 × V × I × PF ÷ 1000. More drills: 3 phase power formula & examples.

What is the 3-phase motor power formula?

Use nameplate or measured P = √3 × V × I × PF × η when efficiency is known; this calculator uses the electrical √3 form without η. Convert HP with 1 HP ≈ 0.746 kW, then solve current or kVA. For transformer kVA from plant kW, use transformer size.

Where is the transformer calculator for 3 phase?

For kVA transformer sizing from load kW and PF, open the kVA transformer calculator. This 3 phase power page computes feeder kW/kVA/current; it does not pick catalog transformer sizes.