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Volts to Amps Calculator

Convert voltage into current for DC, single-phase AC, or three-phase AC using resistance or real power where needed.

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Conversions

Volts to amps calculator: solve current from voltage using resistance or real power

A volts to amps calculator solves current from the electrical relationship that matches the system you are working with. This page supports direct-current circuits with Ohm's Law, plus single-phase and balanced three-phase AC workflows that solve current from real power, voltage, and power factor.

What this volts to amps calculator covers

This tool separates the DC and AC workflows because they start from different known-value patterns. DC mode uses voltage and resistance, which fits the most common Ohm's Law workflow. AC modes instead solve current from real power, voltage, and power factor.

That split keeps the algebra honest and reduces input confusion. If you already know circuit resistance, the DC relationship is the right fit. If you are checking an AC load from power and supply assumptions, the power-based equations reflect that use case much better.

The current formulas behind the result

In DC mode, current equals voltage divided by resistance. In AC modes, the calculator divides real power by voltage and, where required, power factor. Balanced three-phase mode also applies the square-root-of-three factor tied to line-voltage relationships.

The result panel shows the exact working equation used for the selected system so you can audit the arithmetic and confirm that the assumptions match the circuit you are checking.

A = V / R

Use for direct-current circuits when voltage and resistance are known.

A = W / (V x PF)

Use for single-phase AC circuits when voltage, real power, and power factor are known.

A = W / (√3 x V x PF)

Use for balanced three-phase AC circuits with line voltage, real power, and power factor.

How to use the solved current

The current result shows the load implied by the entered operating assumptions. That makes the tool useful for quick plausibility checks, back-solving an operating point, and comparing how the same voltage behaves under DC, single-phase AC, and three-phase AC assumptions.

The supporting real-power figure in AC mode or the implied watt figure in DC mode also helps keep the conversion traceable. If the current looks unrealistic, the issue is often an incorrect resistance, power value, or power factor rather than a problem with the arithmetic.

What this simplified model leaves out

This calculator does not model impedance, reactive power beyond a single entered power factor, efficiency losses, motor-start behaviour, or conductor and breaker sizing. It is a clean algebraic conversion, not a full electrical design or code-compliance tool.

Use it as an educational and planning aid first. For installation work, confirm the result against real measurements, equipment data, and the applicable engineering or code standard.

Frequently asked questions

Why does the DC mode ask for resistance but the AC modes ask for watts?

Because the page uses the most common solving relationship for each workflow. DC mode follows Ohm's Law directly, while the AC modes solve current from real power, voltage, and power factor.

 Why must AC voltage be greater than zero?

The AC formulas divide by voltage, so zero volts would create an invalid divide-by-zero case instead of a meaningful current result.

 Can I use this calculator for wiring or breaker sizing?

No. It only solves current from the entered operating assumptions. Final protection and conductor sizing still require separate code-based checks.

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