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Amps to kW Calculator

Convert amps and volts to real power in kW for DC, AC single-phase, and balanced AC three-phase line-to-line. Runs locally in your browser. Free online tool — no sign-up.

Instant result
Result
—

Enter values to calculate.

Inputs—
Mode—
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 · 10/10 declared partitions (a-kw-dc, a-kw-ac_single, a-kw-ac_three, kw-a-dc, kw-a-ac_single, kw-a-ac_three, invalid-domain, round-trip, metamorphic, near-singularity) · Matrix
Numerical scope
≤2 ULP vs this O2 module on the published golden, near-singularity boundary, round-trip, and metamorphic vectors. Computational fidelity: ULP vs O2. Engineering interpretation: exact deterministic algebraic model; measurement uncertainty is outside calculator scope. Not a whole-domain guarantee (overflow, denormals, or unlisted V→0 neighborhoods). O2 shares Node/V8 binary64 with the IUT; O3 is not required this wave.
Known limitations
  • Balanced sinusoidal; PF ∈ (0,1] on AC. DC omits PF.
  • Core CVP does not include live graph, viewport, or pointer interaction.
Model
Real power in kW from amps and volts (or amps from kW) for DC, AC single-phase, and balanced AC three-phase line-to-line.
Scope
Balanced three-phase when AC 3φ (L-L) is selected.
Verification
Engine tested · Source checked · v1.4.3 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· View Manifest · CVP overview · Specification
Versions
Calculation 1.4.3 · CVP protocol 1.0.0-proposed · Evidence 2026-09-10.evidence-semantics
Verification revision
2026-09-10.evidence-semantics · 5/5 property · digest 1fc8b58b8507
Legacy regression
16/16 tests · Production surface contract 34/34
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
7/7 golden · 4/4 CVP boundary · 6/6 invalid · 5/5 property · 6/6 metamorphic · 6/6 round-trip · 1/1 cross-interface · 2/2 cross-calculator · 34/34 CVP contract · Manifest
Sources
Sources
Evidence
8 legacy golden · 3 legacy boundary · legacy regression suite · 7/7 oracle-backed golden · 6/6 invalid · Artifact integrity PASS · CalculatorX electrical review
This calculator CURRENT · Public schema 1.4.3 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓
Semantic contract
PASS
Full verification

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

Formulas

Core equations used by this calculator.

DCkW = I × V ÷ 1000
AC 1φkW = PF × I × V ÷ 1000
AC 3φ (L-L)kW = √3 × PF × I × VL-L ÷ 1000
AC 3φ (L-N) — reference onlykW = 3 × PF × I × VL-N ÷ 1000Domain: Not selectable in this calculator
iSelectable systems are DC, AC single-phase, and balanced three-phase line-to-line. DC hides power factor. AC 3φ (L-N) is shown as a reference identity only. Real power (kW) = apparent power (kVA) × PF.

How to use

1

Choose Amps → kW or kW → Amps

Forward mode needs current; reverse mode needs real power in kW.

2

Choose the system type

DC, AC single-phase, or balanced AC three-phase. Power factor is hidden for DC.

3

Enter current (or kW) and voltage

For three-phase, enter line-to-line RMS voltage. Read kW (or amps) as the result updates.

Example calculations

Common configurations with formula and result.

ϟ

120 V household

12 A · 120 V · AC 1φ · PF 1

12 × 120 / 1000
1.44 kW
ϟ

240 V DC

40 A · 240 V · DC

40 × 240 / 1000
9.6 kW
ϟ

3φ motor

20 A · 400 V · AC 3φ (L-L) · PF 0.9

√3 × 0.9 × 20 × 400 / 1000
12.471 kW
ϟ

kW → amps

10 kW · 400 V · PF 0.9 · AC 3φ

10000 / (√3 × 400 × 0.9)
16.04 A

Typical power factor (illustrative)

Common values at a glance.

Device / loadTypical PF
Resistive heater / oven1.00
Incandescent lamp1.00
Fluorescent lamp0.95
Induction motor (full load)0.85
Induction motor (no load)0.35
Synchronous motor0.90
Solar / DCN/A — PF not used
i Do not use typical PF values for precise design — use nameplate or measured PF when available.

Amps to kW calculator specification

Version 1.4.3 · Engine tested · Supplemental domain review · Internal · 2026-09-05

Calculation status

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

Definition
Kilowatts (kW) measure real electrical power. Amps measure current. Converting amps to kW needs voltage and, for AC, power factor. This tool computes real power for DC, single-phase AC, and balanced three-phase (line-to-line) circuits, and can reverse the conversion from kW to amps.
What it calculates
Real power in kW from amps and volts (or amps from kW) for DC, AC single-phase, and balanced AC three-phase line-to-line.
Inputs
  • Current I (A) or power P (kW)
  • Voltage V (V); line-to-line for AC 3φ
  • System: DC, AC single-phase, or AC three-phase
  • Power factor PF (0–1) for AC; omitted for DC
Outputs
  • Real power in kilowatts (Amps → kW)
  • Phase current in amperes (kW → Amps)
Formula
DC: P=I·V/1000; 1φ: P=PF·I·V/1000; 3φ L-L: P=√3·PF·I·V/1000
Assumptions
  • Balanced three-phase when AC 3φ (L-L) is selected.
  • Voltage is RMS for AC.
  • DC does not use power factor. AC uses total power factor λ on real power.
Units
  • A, V, PF → kW
  • kW, V, PF → A
Boundary conditions
  • AC power_factor must be in (0, 1] — PF≤0 → FRACTION_OUT_OF_RANGE (dedicated amps-kw engine)
  • Voltage must be > 0 — zero/negative → VOLTAGE_MUST_BE_POSITIVE
  • Zero current yields 0 kW — soft boundary
  • Canonical Agent fields are current_a / power_kw / voltage_v / system / power_factor; REST still accepts a, b, phase, pf
Example
20 A, 400 V, PF 0.9, AC 3φ → 12.471 kW
Validation cases

12 published on this page · 16/16 tests · Production surface contract 34/34 · View evidence

  • 12 A, 120 V, PF 1, AC 1φ → 1.44 kW
  • 40 A, 240 V, DC → 9.6 kW
  • 20 A, 400 V, PF 0.9, AC 3φ → 12.471 kW
  • 10 kW, 400 V, PF 0.9, AC 3φ → A → 16.04 A
  • 24 A, 120 V, PF 1, AC 1φ (2× current) → 2.88 kW (linear in I)
  • 12 A, 240 V, PF 1, AC 1φ (2× voltage) → 2.88 kW (linear in V)
  • 20 A, 400 V, PF 0.45, AC 3φ (half PF) → 6.236 kW (linear in PF)
  • 0 A, 230 V, PF 1, AC 1φ → 0 kW
  • 10 kW, 0 V, PF 1, AC 1φ → A → error VOLTAGE_MUST_BE_POSITIVE
  • 20 A, 400 V, PF 0, AC 3φ → error FRACTION_OUT_OF_RANGE
  • 1.44 kW, 120 V, PF 1, AC 1φ → A → 12 A (round-trip)
  • 16.04 A, 400 V, PF 0.9, AC 3φ → kW → ≈10 kW (round-trip)
Sources
Last reviewed
2026-09-05
Reviewed by
CalculatorX electrical review (electrical-engineer)
Calculation version
1.4.3

Background

Interpretation and common distinctions.

What are amps and kilowatts?

  • Amps (A) — electric current, the rate of electric charge flow through a conductor.
  • Watts (W) — real power; for DC, P = I × V.
  • Kilowatts (kW) — 1 kW = 1000 W, used for larger loads, motors, and solar / battery systems.

Amps alone do not tell you power. You also need voltage, and for AC usually power factor (PF).

Typical power factor values

Device Typical PF
Resistive load / oven 1.00
Incandescent lamp 1.00
Fluorescent lamp 0.95
Induction motor, full load 0.85
Induction motor, no load 0.35
Synchronous motor 0.90
Solar / DC N/A — PF not used

These are ballpark only — not for accurate engineering calculations.

Quick tables (PF = 1, single-phase / DC)

At 120 V

Current (A) Power (kW)
5 0.60
10 1.20
12 1.44
15 1.80
20 2.40
30 3.60
40 4.80
50 6.00
100 12.00

At 240 V

Current (A) Power (kW)
5 1.20
10 2.40
15 3.60
20 4.80
30 7.20
40 9.60
50 12.00
60 14.40
100 24.00

For AC with PF ≠ 1, multiply the table kW by PF. For three-phase line-to-line, multiply by √3 as well (or use the calculator).

Amps and ohms to kW

If you know current and resistance instead of voltage:

P(kW) = I² × R ÷ 1000

kW vs kVA vs watts

Quantity Meaning Relation
W / kW Real power What does work / heats / charges
VA / kVA Apparent power V × I (×√3 for 3φ L-L)
PF Real ÷ apparent kW = kVA × PF

Use Amps to VA for apparent power without PF.

Supported and not supported

Supported — Amps↔kW for DC, single-phase AC, and balanced three-phase L-L · API electrical.amps_to_kw (engine amps-kw)

Not supported — Unbalanced three-phase; L-N three-phase as a selectable mode (reference formula only)

Agent / API notes

Capability id: electrical.amps_to_kw · tool id: amps-to-kw · pin 1.4.3.

Canonical Agent inputs use mode, current_a or power_kw, voltage_v, system (dc | ac_single | ac_three), and power_factor for AC. DC payloads must omit power_factor. REST still accepts a/b, phase, and pf. Output unit is kW for a-kw and A for kw-a. The implementation scale factor=0.001 is not an Agent input. Pin the immutable schema at /schemas/electrical.amps_to_kw/1.4.3/input.json; /schemas/electrical.amps_to_kw.input.json is the latest alias.

Stable errors: MISSING_REQUIRED_INPUT, INVALID_NUMBER, INVALID_MODE, VOLTAGE_MUST_BE_POSITIVE, FRACTION_OUT_OF_RANGE (PF), VALUE_MUST_BE_NON_NEGATIVE.

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Frequently asked questions

Key distinctions behind the calculation.

How do you convert amps to kW?

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

What is the difference between amps, watts, and kilowatts?

Amps measure electric current. Watts measure real power (W = V×I for DC). One kilowatt equals 1000 watts — common for larger loads and solar system sizing.

Do I need power factor?

For DC, no — choose the DC system type and PF is unused. For purely resistive AC loads, use PF = 1. For motors, fluorescent lights, and most AC equipment, PF is less than 1 and must be included to get real power in kW.

What voltage should I enter for three-phase?

Enter line-to-line voltage with AC 3φ (formula uses √3). If you only have line-to-neutral voltage, use the reference identity kW = 3×PF×I×VL-N/1000 — that path is not selectable in this calculator.

How do I model DC in this calculator?

Choose System type DC. Power factor is hidden and unused. That matches P(kW) = I×V/1000.

What is a typical power factor?

Heaters and incandescent lamps ≈ 1. Many induction motors ≈ 0.85 at full load (much lower at no load). Always prefer the equipment nameplate when possible.

How is kW different from kVA?

kVA is apparent power (voltage × current, with √3 for 3φ). kW is real power: kW = kVA × PF. This tool outputs kW in Amps → kW mode and amperes in reverse.

Can I convert kW back to amps?

Yes — use the kW → Amps tab. DC: I = kW×1000/V. AC 1φ: I = kW×1000/(V×PF). AC 3φ L-L: I = kW×1000/(√3×V×PF).