Electrical calculator

Volts to kW Calculator

Estimate kilowatts from voltage, current, and power factor for single-phase and three-phase circuits. Runs locally in your browser. Try it free.

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Instant result

Result

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Enter values to calculate.

Inputs—

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Formula—

Trust summary CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance

Input interpretation: Enter values to calculate.
Result: —
Assurance: Engineering
Declared partition coverage: PASS · 3/3 declared partitions (v-kw, kw-v, invalid-domain) · Matrix
Known limitations: 1φ / 3φ; PF ∈ (0,1]
Core CVP does not include live graph, viewport, or pointer interaction.
Model: Real power in kW from volts, amps, and PF (or volts from kW) for single-phase and three-phase line-to-line.
Scope: Balanced three-phase when √3 mode is selected
Verification: Engine tested · Source checked · v1.3.1 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· View Manifest · CVP overview · Specification
Versions: Calculation 1.3.1 · CVP protocol 1.0.0-proposed · Evidence 2026-09-18.review-policy-l2
Verification revision: 2026-09-18.review-policy-l2 · 1/1 property · digest c2ee30f37cd2
Legacy regression: 12/12 tests · Production surface contract 2/2
Trust layers: Verification VERIFIED · Production CURRENT · overall VERIFIED
Reference: O1 model · O2 expected_values · O2 numerical_behavior
Interfaces: PASS · UI (SSR) / REST / MCP — ui-ssr is query-result HTML, not a live browser session.
Supplemental domain review: Internal · Pass · electrical-engineer
Named expert review: Not performed
CVP suite: 3/3 golden · 3/3 CVP boundary · 4/4 invalid · 1/1 property · 1/1 cross-interface · 2/2 CVP contract · Manifest
Sources: IEC 60050 — International Electrotechnical Vocabulary — Active power (IEV 131-11-42)
IEC 60050 — International Electrotechnical Vocabulary — Power factor (IEV 131-11-46)
IEEE Std 1459-2025 — Real power from voltage, current, and power factor
BIPM SI Brochure (9th edition, version 4.01) — SI units for ampere, volt, and watt
NIST Guide to the SI (SP 811) — Volt, ampere, and watt
Sources
Evidence: 7 legacy golden · 4 legacy boundary · legacy regression suite · 3/3 oracle-backed golden · 4/4 invalid · Artifact integrity PASS · CalculatorX electrical review
Semantic contract: PASS

Full verification

Manifest identity, reference classes, interfaces, suite, and production records.

Formulas

Core equations used by this calculator.

DCkW = V × I ÷ 1000

AC 1φkW = PF × V × I ÷ 1000

AC 3φ (L-L)kW = √3 × PF × VL-L × I ÷ 1000

AC 3φ (L-N)kW = 3 × PF × VL-N × I ÷ 1000

kW → volts (1φ)V = kW × 1000 ÷ (I × PF)

kW → volts (3φ L-L)V = kW × 1000 ÷ (√3 × I × PF)

iUI uses single-phase (ph = 1) or three-phase line-to-line (ph = √3). For DC, choose single phase and set PF = 1. Enter RMS volts for AC. Real power (kW) = apparent power (kVA) × PF.

How to use

Choose Volts → kW or kW → Volts

Forward mode needs V and I; reverse mode needs kW and I.

Enter voltage (or kW), current, and PF

For three-phase, enter line-to-line voltage. For DC, set PF = 1 and use single phase.

Select single or three phase

Three-phase multiplies by √3 ≈ 1.732. Read kW (or volts) as the result updates.

Example calculations

Common configurations with formula and result.

DC / resistive 240 V

240 V · 10 A · PF 1

240 × 10 / 1000

2.4 kW

120 V household

120 V · 12 A · PF 1

120 × 12 / 1000

1.44 kW

AC 1φ with PF

230 V · 16 A · PF 0.9

0.9 × 230 × 16 / 1000

3.312 kW

3φ motor

400 V · 20 A · PF 0.9

√3 × 0.9 × 400 × 20 / 1000

12.471 kW

kW → volts

2.4 kW · 10 A · PF 1 · 1φ

2400 / (10 × 1)

240 V

Quick volts → kW (PF = 1, single-phase / DC)

Common values at a glance.

Voltage	Current	Power
120 V	10 A	1.2 kW
120 V	15 A	1.8 kW
240 V	10 A	2.4 kW
240 V	20 A	4.8 kW
48 V	20 A	0.96 kW
400 V · 3φ · PF 0.9 · 20 A	—	12.471 kW

i 1 kW = 1000 W. ≈ 1.34 HP (mechanical conversion varies by definition; electrical HP often uses 746 W).

Volts to kW calculator specification

Version 1.3.1 · Engine tested · Supplemental domain review · Internal · 2026-08-08

Calculation status

Engine tested 12/12 tests · Production surface contract 2/2
Supplemental domain review Internal · Pass · electrical-engineer · 2026-08-08
Named expert review Not performed
Calculation version 1.3.1

Review policy · Evidence · Reviewed by CalculatorX electrical review (electrical-engineer)

Definition: Kilowatts (kW) are real electrical power. You cannot convert volts to kW from voltage alone — you also need current, and for AC a power factor. DC: P(kW) = V×I/1000. Single-phase AC: P = PF×V×I/1000. Three-phase (line-to-line): P = √3×PF×VL-L×I/1000. This tool also solves for voltage from kW, amps, and PF.
What it calculates: Real power in kW from volts, amps, and PF (or volts from kW) for single-phase and three-phase line-to-line.
Inputs: Voltage V (V) or power P (kW)
Current I (A)
Power factor PF (0–1)
Phase: single or three
Outputs: Real power in kilowatts (Volts → kW)
Voltage in volts (kW → Volts)
Formula: 1φ: P=PF·V·I/1000; 3φ L-L: P=√3·PF·V·I/1000
Assumptions: Balanced three-phase when √3 mode is selected
Voltage is RMS for AC
PF = 1 for DC / resistive
Units: V, A, PF → kW
Boundary conditions: power_factor must be in (0, 1] — PF≤0 → FRACTION_OUT_OF_RANGE (engine volts-kw)
Voltage must be > 0 on Volts→kW — VOLTAGE_MUST_BE_POSITIVE
Current must be > 0 on kW→Volts — VALUE_MUST_BE_POSITIVE
Zero current on forward yields 0 kW — soft boundary
Example: 240 V, 10 A, PF 1, 1φ → 2.4 kW
Validation cases: 13 published on this page · 12/12 tests · Production surface contract 2/2 · View evidence
240 V, 10 A, PF 1, 1φ → 2.4 kW
120 V, 12 A, PF 1, 1φ → 1.44 kW
400 V, 20 A, PF 0.9, 3φ → 12.471 kW
2.4 kW, 10 A, PF 1, 1φ → V → 240 V
480 V, 10 A, PF 1, 1φ (2× V) → 4.8 kW (linear in V)
240 V, 20 A, PF 1, 1φ (2× I) → 4.8 kW (linear in I)
400 V, 20 A, PF 0.45, 3φ (half PF) → 6.236 kW (linear in PF)
240 V, 0 A, PF 1, 1φ → 0 kW
0 V, 10 A, PF 1, 1φ → 0 kW
2.4 kW, 0 A, PF 1, 1φ → V → 0 V (soft: zero current → 0 V)
240 V, 10 A, PF 0, 1φ → 2.4 kW (engine treats PF ≤ 0 as 1)
230 V, 10 A, PF 0.8, 1φ → 1.84 kW
2.4 kW → V → kW round-trip at 10 A, PF 1, 1φ → 2.4 kW
Sources: IEC 60050 — International Electrotechnical Vocabulary — Active power (IEV 131-11-42) · accessed 2026-09-05
Supports: P is active power; unit watt (W). Under sinusoidal conditions P = Re S.
IEC 60050 — International Electrotechnical Vocabulary — Power factor (IEV 131-11-46) · accessed 2026-09-05
Supports: λ = |P| / S; AC real-power formulas multiply V·I (and √3 for 3φ L-L) by λ
IEEE Std 1459-2025 — Real power from voltage, current, and power factor · 2025-05-16 · errata checked · accessed 2026-09-05
Supports: 1φ P = PF·V·I/1000; 3φ L-L P = √3·PF·V·I/1000; DC P = V·I/1000
BIPM SI Brochure (9th edition, version 4.01) — SI units for ampere, volt, and watt · 2026-06 · DOI · accessed 2026-09-05
Supports: DC P = V·I; kW = 1000 W unit scaling
NIST Guide to the SI (SP 811) — Volt, ampere, and watt
Supports: SI unit relationships in power calculations
Last reviewed: 2026-08-08
Reviewed by: CalculatorX electrical review (electrical-engineer)
Calculation version: 1.3.1

Background

Interpretation and common distinctions.

Convert volts and amps to kilowatts (real power) — or solve for voltage from kW and current.

You always need current (and power factor for AC). Voltage alone is not power.

Power factor tips

Load	Typical PF
Resistive heater / oven	1.00
Incandescent lamp	1.00
Induction motor (full load)	~0.85
Many nameplate motors	0.8–0.9

Prefer nameplate or measured PF for design. Improving PF reduces kVA demand for the same kW.

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Frequently asked questions

Key distinctions behind the calculation.

How do you convert volts to kW?

Multiply voltage by current (and power factor for AC), then divide by 1000. DC: kW = V×I/1000. Single-phase AC: kW = PF×V×I/1000. Three-phase (line-to-line): kW = √3×PF×VL-L×I/1000.

Can I convert volts to kW without amps?

No. Volts alone are potential, not power. You need current (and PF for AC), or another path such as known watts / 1000.

How do I model DC?

Choose single phase and set PF = 1. That matches P(kW) = V×I/1000.

What voltage should I enter for three-phase?

Enter line-to-line RMS voltage with the three-phase option (formula uses √3). If you only have line-to-neutral, use kW = 3×PF×I×VL-N/1000 instead (not the default UI path).

Do I need power factor?

For DC or purely resistive AC (heaters, many ovens), use PF = 1. Motors and many inductive loads need the nameplate or measured PF (often 0.8–0.9) to get real kW.

How is kW different from kVA?

kVA is apparent power; kW is real power. kW = kVA × PF. This calculator outputs kW.

Can I convert kW back to volts?

Yes — use the kW → Volts tab: V = kW×1000 / (√3 (3φ only) × I × PF), with √3 only for three-phase line-to-line.

What about horsepower?

Roughly 1 HP ≈ 0.746 kW (electrical). Convert kW first, then divide by 0.746 if you need HP.