Electrical calculator

Amps to VA Calculator

Convert amps and volts to apparent power in VA or kVA for single-phase and three-phase circuits. Also convert VA back to amps. Fast and free.

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Result

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Enter values to calculate.

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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 · 5/5 declared partitions (amps-va-1phi, amps-va-3phi, va-amps, amps-kva, invalid-domain) · Matrix
Known limitations: PF optional for derived real power only — not applied to S
Core CVP does not include live graph, viewport, or pointer interaction.
Model: Apparent power in VA or kVA from amps and volts, or amps from VA, for 1φ and balanced sinusoidal 3φ line-to-line AC; optional estimated real power from total power factor λ.
Scope: AC steady-state with RMS voltage and current magnitudes.
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.cvp-bootstrap
Verification revision: 2026-09-10.cvp-bootstrap · 14/14 property · digest c57787417bc3
Legacy regression: 36/36 tests · Production surface contract 4/4
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: Not performed
Named expert review: Not performed
CVP suite: 4/4 golden · 12/12 CVP boundary · 10/10 invalid · 14/14 property · 1/1 cross-interface · 4/4 CVP contract · Manifest
Sources: IEC 60050 — International Electrotechnical Vocabulary — Apparent power (IEV 131-11-41)
IEC 60050 — International Electrotechnical Vocabulary — Power factor (IEV 131-11-46)
IEEE Std 1459-2025 — Definitions for electric power measurement under sinusoidal, nonsinusoidal, balanced, or unbalanced conditions
BIPM SI Brochure (9th edition, version 4.01) — SI base and derived units for ampere, volt, and power
Sources
Evidence: 9 legacy golden · 13 legacy boundary · legacy regression suite · 4/4 oracle-backed golden · 10/10 invalid · Artifact integrity PASS
Semantic contract: PASS

Full verification

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

Formulas

Core equations used by this calculator.

Single-phase apparent powerS = V_RMS × I_RMS

Three-phase (L-L, balanced sinusoidal)S = √3 × V_L-L × I_L

kVAS_kVA = S_VA ÷ 1000

Estimated real power (optional)P_est = S × λ_entered

iS is apparent power; VA is the unit. Everyday form of the same math: VA = I × V. Apparent power does not use power factor. Three-phase mode is balanced sinusoidal AC with line-to-line RMS voltage, where V_LL = √3 V_LN and line currents are equal. IEEE 1459 covers a wider set of conditions; this calculator does not. Total power factor λ is optional and estimates watts on the page and in REST/MCP as derived.estimated_real_power; λ in [0, 1] is accepted. λ=0 means zero real power with non-zero apparent power (an ideal purely reactive sinusoidal load is one example). 1 kVA = 1000 VA. Not for DC, unbalanced, or nonsinusoidal three-phase.

How to use

Choose Amps → VA, VA → Amps, or Amps → kVA

Forward modes need current; reverse needs apparent power in VA.

Enter current (or VA) and voltage

Voltage must be greater than zero. For three-phase, enter balanced sinusoidal line-to-line volts.

Optional: estimate real power

Open Advanced and enter total power factor λ in [0, 1]. Not required for VA/kVA. λ=0 means zero real power with S>0 (an ideal purely reactive sinusoidal load is one example); use 0.8 for 80%.

Example calculations

Common configurations with formula and result.

Single-phase household

20 A at 120 V

S = 120 × 20

2,400 VA

Single-phase 230 V

12 A at 230 V

S = 230 × 12

2,760 VA

Three-phase

10 A at 400 V L-L

S = √3 × 400 × 10

6,928 VA

Three-phase large

60 A at 480 V L-L

S = √3 × 480 × 60

49,883 VA

Amps → kVA

12 A · 230 V · 1φ

S_kVA = 230 × 12 / 1000

2.760 kVA

Quick VA examples

Common values at a glance.

Current	Voltage	Phase	Formula	Apparent power
5 A	120 V	1φ	S = 120 × 5	600 VA
20 A	120 V	1φ	S = 120 × 20	2,400 VA
12 A	230 V	1φ	S = 230 × 12	2,760 VA
15 A	230 V	1φ	S = 230 × 15	3,450 VA
10 A	400 V	3φ	S = √3 × 400 × 10	6,928 VA
20 A	400 V	3φ	S = √3 × 400 × 20	13,856 VA
60 A	480 V	3φ	S = √3 × 480 × 60	49,883 VA

i Rounded to the nearest VA. Three-phase uses balanced sinusoidal line-to-line voltage.

Amps to VA calculator specification

Version 1.4.3 · Engine tested

Calculation status

Engine tested 36/36 tests · Production surface contract 4/4
Named expert review Not performed
Calculation version 1.4.3

Review policy · Evidence

Definition: Volt-amperes (VA) measure apparent electrical power — the product of RMS voltage and RMS current, without power factor. This calculator converts amps ↔ VA and amps → kVA for single-phase and balanced sinusoidal three-phase line-to-line AC. An optional total power factor (λ) field estimates real power on the page and in the API as derived.estimated_real_power (P_est = S × λ_entered).
What it calculates: Apparent power in VA or kVA from amps and volts, or amps from VA, for 1φ and balanced sinusoidal 3φ line-to-line AC; optional estimated real power from total power factor λ.
Inputs: Current I (A) or apparent power S (VA)
Voltage V (V), must be > 0; line-to-line RMS for 3φ
Phase: single or three (balanced sinusoidal L-L only)
Optional total power factor λ in [0, 1] for estimated real power (page + API derived.estimated_real_power)
Outputs: Apparent power in VA
Apparent power in kVA
Current in A (VA → Amps)
Optional estimated real power in W (page UI and API derived.estimated_real_power when λ is supplied)
Formula: 1φ: S=V_RMS·I_RMS; 3φ L-L balanced sinusoidal: S=√3·V_L-L·I_L; S_kVA=S_VA/1000; P_est=S·λ_entered (when λ supplied)
Assumptions: AC steady-state with RMS voltage and current magnitudes.
Three-phase mode is balanced sinusoidal AC using line-to-line RMS voltage, where V_LL = √3 V_LN and line currents are equal. IEEE 1459 covers a wider set of conditions; this calculator does not.
Total power factor λ is not applied to VA/kVA results.
Units: A, V → VA or kVA
Boundary conditions: Missing or non-positive voltage returns an error (UI and API); never a fake 0 A / 0 VA
Power factor outside [0, 1] is rejected when provided; not silently ignored. λ=0 is accepted (P_est=0 when S>0).
Negative primary (current or VA) is rejected
Overflow to Infinity or NaN is rejected as NON_FINITE_RESULT; never returned as a success result
Example: 12 A, 230 V, 1φ → S = 2,760 VA (2.760 kVA)
Validation cases: 20 published on this page · 36/36 tests · Production surface contract 4/4 · View evidence
20 A, 120 V, 1φ → 2400 VA
12 A, 230 V, 1φ → 2760 VA
10 A, 400 V, 3φ L-L → 6928 VA
60 A, 480 V, 3φ L-L → 49883 VA
2760 VA, 230 V, 1φ → A → 12 A
24 A, 230 V, 1φ (2× current) → 5520 VA
12 A, 460 V, 1φ (2× voltage) → 5520 VA
PF = 1 (accepted; VA unchanged) → 1200 VA for 10 A × 120 V
10 A, 120 V, 1φ, PF=0 → 1200 VA · P_est = 0 W
VA → Amps with volts = 0 → error VOLTAGE_MUST_BE_POSITIVE
volts = -230 → error VOLTAGE_MUST_BE_POSITIVE
primary = -5 A → error VALUE_MUST_BE_NON_NEGATIVE
PF = 80 → error POWER_FACTOR_OUT_OF_RANGE
unknown mode → error INVALID_MODE
unknown phase → error INVALID_PHASE
primary = 0 A, 230 V, 1φ → 0 VA
10 A, 400 V, 3φ L-L → kVA → 6.928 kVA
6928.203 VA, 400 V, 3φ L-L → A → 10 A
missing volts → error MISSING_REQUIRED_INPUT
1e308 A × 1e308 V → error NON_FINITE_RESULT
Sources: IEC 60050 — International Electrotechnical Vocabulary — Apparent power (IEV 131-11-41) · accessed 2026-09-04
Supports: S = U × I definition of apparent power; unit volt-ampere (VA)
IEC 60050 — International Electrotechnical Vocabulary — Power factor (IEV 131-11-46) · accessed 2026-09-04
Supports: λ = |P| / S, so λ = 0 when P = 0 and S > 0; optional page/API estimate P_est = S × λ_entered uses this definition
IEEE Std 1459-2025 — Definitions for electric power measurement under sinusoidal, nonsinusoidal, balanced, or unbalanced conditions · 2025-05-16 · errata checked · accessed 2026-09-04
Supports: IEEE 1459 covers sinusoidal, nonsinusoidal, balanced, and unbalanced conditions. This calculator implements only the balanced sinusoidal three-phase model S = √3 × V_L-L × I_L (V_LL = √3 V_LN, equal line currents).
BIPM SI Brochure (9th edition, version 4.01) — SI base and derived units for ampere, volt, and power · 2026-06 · DOI · accessed 2026-09-04
Supports: V, A, W, and VA unit relationships
Calculation version: 1.4.3

Background

Interpretation and common distinctions.

What are amps and VA?

Amps (A) — electric current.
Volt-amperes (VA) — apparent power: how much voltage × current the circuit presents to the supply.
Kilovolt-amperes (kVA) — 1 kVA = 1000 VA, common for transformers and larger AC equipment.

Apparent power is the product of RMS voltage and RMS current: S = V_RMS × I_RMS. Unlike real power, apparent power itself does not apply power factor. Quantity symbol S, unit VA.

Supported and not supported

Supported

Single-phase AC
Balanced sinusoidal three-phase AC with line-to-line RMS voltage (V_LL = √3 V_LN, equal line currents)
RMS voltage and current magnitudes
Amps ↔ VA and Amps → kVA

Not supported

DC systems (use watts / Amps to kW style real-power tools)
Unbalanced three-phase, unequal per-phase currents, or nonsinusoidal / harmonic-rich three-phase (the √3 formula does not apply)
Line-to-neutral voltage as a separate three-phase mode
Phase-angle, harmonic, or protection calculations
Breaker, cable, or equipment sizing / compliance decisions

VA vs watts vs kW

Quantity	Meaning	Formula idea
VA / kVA	Apparent power	S = V_RMS × I_RMS (×√3 for balanced sinusoidal 3φ L-L)
W / kW	Real power	P_est = S × λ (total power factor, when entered)
λ (PF)	Real ÷ apparent	0 ≤ λ ≤ 1

UPS, inverters, and transformers are often rated in VA/kVA.
Utility bills and heating loads care about watts/kW.
For real power from current, use Amps to kW.

Other calculators in this family: Amps to kW Calculator, Amps to Volts Calculator, Electric Power Calculator, Energy Consumption Calculator, Energy Cost Calculator, eV to Volts Calculator, kVA to Amps Calculator, kVA to kW Calculator . Explore all Power & Energy.

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Frequently asked questions

Key distinctions behind the calculation.

What is VA (volt-amperes)?

VA is apparent electrical power: the product of RMS voltage and RMS current. It describes how hard the supply and wiring are loaded, before separating real and reactive power.

How do I convert amps to VA?

Single-phase: S = V_RMS × I_RMS. Balanced sinusoidal three-phase with line-to-line voltage: S = √3 × V_L-L × I_L. Everyday form of the same math: VA = I × V. This page does not accept line-to-neutral voltage as a separate mode.

Do I need power factor for VA?

No. Total power factor λ is optional and estimates real power: P_est = S × λ_entered (page UI and API derived.estimated_real_power). Apparent power itself does not multiply by λ. λ = 0 means zero real power with non-zero apparent power; an ideal purely reactive sinusoidal load is one example.

How is VA different from watts?

VA is apparent power; watts are real power consumed as work or heat. For resistive loads λ ≈ 1 so VA ≈ W. For motors and many AC loads, watts are lower than VA.

What voltage do I enter for three-phase?

Enter balanced sinusoidal line-to-line RMS voltage with the three-phase option, where V_LL = √3 V_LN and line currents are equal. The calculator multiplies by √3. Line-to-neutral, unbalanced, and nonsinusoidal three-phase are not supported on this page.

What is the difference between VA and kVA?

1 kVA = 1000 VA. Use Amps → kVA for the same math divided by 1000 — handy for transformers and larger equipment.

Can I convert VA back to amps?

Yes — use VA → Amps: I = S / V_RMS (single-phase) or I = S / (√3 × V_L-L) (three-phase). Voltage must be greater than zero.

What if voltage is missing or zero?

The calculator and API reject the request. Missing or zero voltage is not treated as a valid result of 0 A or 0 VA.

Why do some sites multiply VA by power factor?

That gives watts (or a PF-adjusted figure), not true apparent power. Standard definition: S = V_RMS × I_RMS (× √3 for balanced sinusoidal 3φ L-L), without PF.