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Amps to Watts Calculator

Convert amps to watts for DC, AC & 3-phase circuits

W = A × V × PF

Amps to Watts Calculator

Enter your values above to instantly calculate the electrical power.

Live Result
Formula-backed — instant professional result
System Type
CALCULATED POWER
0 W
Also equals 0 kW
Formula used W = A × V The primary result is shown in W using the formula displayed above. 10A × 120V × 1.0 = 1200W

This calculator is an educational planning estimate. Verify safety-critical work with equipment nameplate data, local electrical code, and a qualified professional.

Amps to Watts — Quick Answer

To convert amps to watts, multiply amps by volts.

Watts = Amps × Volts

For AC loads with power factor:

Watts = Amps × Volts × Power Factor

For three-phase line-to-line power:

Watts = 1.732 × Amps × Volts × Power Factor

This free amps to watts calculator converts electrical current (amps) into real power (watts). Enter current, voltage, and power factor when needed, then choose DC, single-phase AC, or three-phase AC for accurate watts and kilowatts results. Ideal for appliance wattage, battery systems, generator load planning, EV charger circuits, and motor estimates. See the amps to watts formula or conversion chart for quick reference.

DC, Single-Phase & Three-Phase Supports all common current types in one tool
Correct Formula for Each Type Uses industry-standard formulas with power factor
Watts & Kilowatts Output Results in both watts and kW for quick reference
Appliances, Solar, EVs & More Helpful for batteries, generators, motors, and chargers

How to Use the Amps to Watts Calculator

Follow these steps to convert amps to watts for any circuit type.

To calculate watts from amps, choose the current type, enter the current in amps, enter the voltage, and add power factor for AC loads. The calculator shows the estimated power in watts and kilowatts.

Current type Choose DC, single-phase AC, or three-phase AC depending on your circuit.
Current (amps) Enter the load current in amps from the equipment nameplate or a clamp meter reading.
Voltage (volts) Enter the circuit or device voltage. Common values: 12V, 24V, 120V, 208V, 240V, 277V, 480V.
Power factor Use 1.0 for resistive loads (heaters, lights) or the nameplate value for motors and AC equipment. If unknown, 0.85 is a safe estimate.
Voltage type (three-phase) For three-phase systems, choose line-to-line or line-to-neutral. Most industrial equipment uses line-to-line voltage.

Amps to Watts Formulas

The correct formula depends on your circuit type — DC, AC single-phase, or AC three-phase.

DC Direct Current

W = A × V

For DC circuits, multiply amps by volts to get watts. No power factor needed because current and voltage stay in phase.

5A × 12V = 60 watts
1Φ Single-Phase AC

W = A × V × PF

For AC single-phase circuits, include the power factor to account for reactive power in inductive loads.

10A × 120V × 1.0 = 1,200 watts
3Φ L-L Three-Phase AC (Line-to-Line)

W = √3 × A × V × PF

Three-phase line-to-line systems use the √3 (1.732) multiplier because power is shared across three phases.

10A × 480V × 0.90 × 1.732 = 7,478W
3Φ L-N Three-Phase AC (Line-to-Neutral)

W = 3 × A × V × PF

When using line-to-neutral voltage in three-phase systems, multiply by 3 instead of √3.

10A × 277V × 0.90 × 3 = 7,479W

DC circuits use amps and volts directly — power equals current times voltage. AC circuits often need power factor because not all apparent power becomes real power. Inductive loads like motors and compressors draw reactive current that does no useful work, which lowers the power factor below 1.0. Three-phase systems need a different multiplier because electrical power is distributed across three conductors with a 120° phase offset.

Note: These formulas calculate watts (real power), not watt-hours or kilowatt-hours. Watts measure instantaneous power consumption. To find energy usage over time, multiply watts by hours.

DC Amps to Watts

Direct current conversion is the simplest case.

In a DC circuit — such as a battery, solar panel, or automotive system — converting amps to watts requires only the current and voltage: Watts = Amps × Volts. There is no power factor in DC because the current and voltage waveforms do not alternate. A 12V battery delivering 5 amps produces exactly 60 watts of real power. This formula applies to all DC applications, from USB chargers at 5V to solar arrays at 48V and telecommunications systems at 24V or 48V.

Use the DC amps to watts calculator for a dedicated tool pre-configured for direct current, or 12V, 24V voltage-specific calculators for common battery systems.

AC Single-Phase Amps to Watts

Most household and small commercial circuits are single-phase AC.

For AC single-phase circuits, the amps to watts formula includes power factor: Watts = Amps × Volts × Power Factor. Resistive loads like heaters, incandescent lights, and toasters have a power factor of 1.0, which means all the apparent power becomes real power. Inductive loads such as motors, compressors, and fluorescent ballasts have a lower power factor — typically between 0.70 and 0.95 — so their real power is less than the simple amps × volts product.

For most standard household appliances on 120V or 240V circuits, the amps to watts conversion is straightforward. Use the AC amps to watts calculator or the single-phase amps to watts tool for pre-configured single-phase calculations.

Three-Phase Amps to Watts

Industrial and commercial power systems typically use three-phase AC.

Three-phase amps to watts conversion uses a different multiplier depending on whether you measure line-to-line or line-to-neutral voltage. For line-to-line voltage (the most common measurement): Watts = √3 × Amps × Volts × PF, where √3 ≈ 1.732. For line-to-neutral voltage: Watts = 3 × Amps × Volts × PF.

The √3 factor accounts for the 120° phase offset between the three power conductors. Common three-phase voltages include 208V, 400V, 480V, and 600V (line-to-line). Use the 3-phase amps to watts calculator for a dedicated three-phase tool with line-to-line and line-to-neutral options.

Real-World Amps to Watts Examples

Practical examples of converting amps to watts in common electrical systems.

12V DC Battery

5A × 12V = 60W

A 12V device drawing 5 amps uses about 60 watts. Common in automotive, RV, and solar battery systems.

120V Appliance

10A × 120V × 1.0 = 1,200W

A 120V resistive appliance drawing 10 amps uses about 1,200 watts. Typical for hair dryers, toasters, and space heaters.

240V Load

30A × 240V × 1.0 = 7,200W

A 240V load drawing 30 amps can use about 7.2 kW. Common for electric dryers, EV chargers, and water heaters.

480V Three-Phase

10A × 480V × 0.90 × 1.732 = 7,478W

A 480V three-phase load at 10 amps and 0.90 power factor uses about 7.48 kW. Typical for industrial motors and commercial HVAC.

Amps to Watts Conversion Chart

Quick reference for DC and resistive AC loads (power factor = 1.0).

Amps (A) Voltage (V) Watts (W)
1A 12V 12W
5A 12V 60W
10A 12V 120W
1A 120V 120W
5A 120V 600W
10A 120V 1,200W
10A 240V 2,400W
30A 240V 7,200W

For AC loads with power factor below 1.0, actual watts will be lower than amps × volts. Multiply the result by the equipment's power factor (found on the nameplate) to get real power.

Amps vs Watts vs Volts

Understanding the core electrical units used in power calculations.

Amps (Amperes)

Amps measure electrical current — the rate of electron flow through a conductor. Higher amperage means more current, which typically requires larger wire and higher-rated circuit breakers.

Volts (Voltage)

Volts measure electrical pressure or potential difference — the force that pushes current through a circuit. Common voltages include 12V (batteries), 120V (US outlets), 230V (EU outlets), and 480V (industrial).

Watts (Power)

Watts measure real electrical power — the rate at which energy is consumed or converted into heat, light, or motion. Watts = Amps × Volts for DC and resistive loads.

Power Factor

Power factor (PF) indicates how effectively AC power becomes usable real power. It ranges from 0 to 1.0, where 1.0 means all apparent power is real power. Motors and compressors typically have PF between 0.70 and 0.95.

Kilowatts (kW)

Kilowatts equal watts divided by 1,000. Professional and industrial equipment ratings often use kW because values in the thousands of watts are more practical to express in kilowatts.

When Power Factor Matters

Not every amps to watts conversion needs power factor.

For purely resistive loads — heaters, incandescent lights, toasters, and kettles — power factor is 1.0, and the simple formula Watts = Amps × Volts gives the correct result. Power factor becomes important when the load includes inductive components like motors, compressors, fluorescent lighting ballasts, and transformers.

If you are estimating appliance wattage for a household device, you can usually ignore power factor. For generator sizing, electrical panel planning, and industrial circuit load calculations, always include the power factor from the equipment nameplate. Learn more in our power factor guide.

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Amps to Watts — Our Core Specialty

Ampstowatt.com is built entirely around the amps to watts conversion. Every calculator, guide, and chart on this site helps you convert electrical current (amps) into real power (watts) — accurately, instantly, and for free.

Whether you need to convert amps to watts for a 120V household outlet, a 12V battery, a 240V EV charger, or a 480V three-phase motor, this is the authoritative resource. Our formulas follow Watt's Law and industry-standard AC/DC power equations used by electricians, engineers, and homeowners worldwide.

Safety & Accuracy

This calculator provides educational power estimates based on the values entered. For wiring, breaker sizing, voltage drop, code compliance, or safety-critical electrical work, verify the device nameplate data and consult a licensed electrician.

Built for Accuracy. Designed for Everyone.

Built for homeowners, students, technicians, electricians, and anyone who needs fast electrical power estimates.

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Methodology, Review Notes, and Sources

How this calculator works

The calculator applies Watt's law for DC and resistive loads, then adds power factor for AC loads and the 1.732 multiplier for balanced three-phase line-to-line calculations.

  • DC and resistive loads: W = A x V
  • Single-phase AC: W = A x V x PF
  • Three-phase AC: W = 1.732 x A x V x PF

Editorial review

Last reviewed: June 26, 2026. Ampstowatt.com is built around the amps to watts conversion — our core specialty. Content is maintained by the Ampstowatt editorial team and checked for formula consistency, unit labels, calculator behavior, and safety wording.

The page is an educational planning reference, not a licensed electrical design or inspection service.

Reference sources

FAQ

Frequently Asked Questions

Fast answers for the amps to watts formula, common conversions, and safe planning limits.

W How do I convert amps to watts?

Multiply amps by volts to get watts. For example, 10 amps at 120 volts equals 1,200 watts (10 × 120 = 1,200). For AC circuits with motors or compressors, also multiply by the power factor from the equipment nameplate.

AC What is the formula for amps to watts?

There are three formulas depending on the circuit type. DC: Watts = Amps × Volts. AC single-phase: Watts = Amps × Volts × Power Factor. AC three-phase (line-to-line): Watts = 1.732 × Amps × Volts × Power Factor. For three-phase line-to-neutral: Watts = 3 × Amps × Volts × Power Factor.

1A How many watts are in 1 amp?

1 amp equals a different number of watts depending on the voltage. At 12V, 1 amp = 12 watts. At 120V, 1 amp = 120 watts. At 240V, 1 amp = 240 watts. This assumes power factor of 1.00. For AC motor loads with lower power factor, the real watts will be lower.

V Do I need voltage to convert amps to watts?

Yes — you cannot convert amps to watts without knowing the voltage. Amps measure current flow, and watts measure power. The relationship is Watts = Amps × Volts. Without voltage, there is no way to determine how much power the current represents. A 10-amp load could be 120 watts (at 12V) or 2,400 watts (at 240V).

PF Why does AC amps to watts need power factor?

Power factor (PF) measures how efficiently a device uses current. Resistive loads like heaters use all the current for real work (PF = 1.0). Motors and compressors draw extra current due to inductance, so their power factor is lower (0.70–0.95). Without accounting for PF, you would overestimate watts by 10–40% for these loads.

VS What is the difference between amps and watts?

Amps (amperes) measure the flow rate of electric current — how much charge passes a point per second. Watts measure electric power — the rate at which electrical energy is used or converted to heat, light, or motion. You need both amps and volts to calculate watts: Watts = Amps × Volts.

3P How do I convert three-phase amps to watts?

For three-phase with line-to-line voltage: Watts = √3 × Amps × Volts × Power Factor (√3 ≈ 1.732). For line-to-neutral voltage: Watts = 3 × Amps × Volts × PF. Example: 10A at 480V with PF 0.90 using line-to-line voltage = 1.732 × 10 × 480 × 0.90 = 7,478 watts.

Wh Is watts the same as watt-hours?

No. Watts (W) measure instantaneous power — how fast energy is being used right now. Watt-hours (Wh) measure total energy consumed over time. A 100-watt light bulb running for 3 hours uses 300 watt-hours (0.3 kWh). Your electricity bill charges per kilowatt-hour, not per watt.

APP Can I use this calculator for appliances?

Yes. Enter the amperage from the appliance nameplate, the outlet voltage (120V or 240V in the US), and power factor if listed. For resistive appliances (heaters, toasters, hair dryers), use PF = 1.0. For motor-driven appliances (refrigerators, AC units, washing machines), use the nameplate PF or estimate 0.85.

SA Can I use this calculator for breaker or wire sizing?

You can use the result for load planning, but not for final breaker or wire sizing. The NEC requires that continuous loads (3+ hours) stay at or below 80% of the breaker rating. Final sizing must account for wire gauge, ambient temperature, conduit fill, voltage drop, and local code. Always consult a licensed electrician for safety-critical work.