How do you convert watts to amps?

To convert watts to amps, divide watts by volts. DC formula: Amps = Watts ÷ Volts. AC single-phase: Amps = Watts ÷ (Volts × Power Factor). AC three-phase: Amps = Watts ÷ (1.732 × Volts × Power Factor).

How many amps is 2000 watts?

2000 watts at 120V = 16.67 amps (DC or AC PF 1.0). At 240V = 8.33 amps. At 240V AC with PF 0.8 = 10.42 amps. The voltage and power factor both change the result.

How many amps is 1500 watts?

1500 watts at 120V = 12.5 amps. At 240V = 6.25 amps. A 1500-watt heater on a 120V circuit draws 12.5 amps — you need at least a 15-amp breaker (20-amp recommended per NEC 80% rule).

How many amps is 1000 watts?

1000 watts at 120V DC = 8.33 amps. At 120V AC with PF 0.8 = 10.42 amps. At 240V DC = 4.17 amps. Use our Watts to Amps Calculator above for any combination of watts, volts and power factor.

How many amps is 500 watts?

500 watts at 120V = 4.17 amps. At 12V DC (like solar or automotive) = 41.67 amps. Voltage has a huge effect — always specify your system voltage when calculating amps from watts.

How many amps is 100 watts?

100 watts at 120V = 0.83 amps. At 12V DC = 8.33 amps. At 240V = 0.42 amps. A 100-watt light bulb on a standard 120V US household circuit draws less than 1 amp.

What is the watts to amps formula?

DC: Amps = Watts ÷ Volts. AC Single Phase: Amps = Watts ÷ (Volts × Power Factor). AC Three Phase: Amps = Watts ÷ (√3 × Volts × Power Factor). For DC circuits, simply divide watts by volts. For AC circuits, you must also account for power factor.

How many amps does a 1500 watt heater use?

A 1500-watt heater on a 120V circuit uses 12.5 amps. On a 240V circuit it uses 6.25 amps. Space heaters are resistive loads so power factor = 1.0. Always use a dedicated 20-amp circuit for a 1500W heater on 120V.

What is power factor in electricity?

Power factor (PF) is the ratio of real power (watts) to apparent power (VA) in an AC circuit. It ranges from 0 to 1. Resistive loads like heaters have PF=1. Inductive loads like motors have PF of 0.7–0.9, meaning they draw more current than their watt rating suggests.

How do I calculate amps from watts and volts?

Divide watts by volts to get amps: Amps = Watts ÷ Volts. For a 2000W device at 240V: 2000 ÷ 240 = 8.33 amps. For AC circuits, also divide by the power factor: Amps = Watts ÷ (Volts × PF).

Watts to Amps Calculator – Convert W to A (DC, AC Single & 3 Phase)

Electrical Calculator

Watts to Amps Calculator

The fastest way to convert power (W) to current (A) for DC, AC Single Phase, and AC Three Phase systems — with formula breakdown and downloadable results.

Watts → Amps Converter

Enter values below and click Calculate

Select Current Type

Power (W)

Voltage (V)

Power Factor

Quick Voltage →

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NEC Safety Tip: Always size circuit breakers at 125% of calculated amps for continuous loads — required by the National Electrical Code (NEC 210.19).

Formulas

A = W ÷ V

AC Single Phase

A = W ÷ (V × PF)

AC Three Phase

A = W ÷ (√3 × V × PF)

Quick Reference

Watts	@120V	Amps
100W	DC	0.83 A
500W	120V	4.17 A
1000W	120V	8.33 A
1500W	240V	6.25 A
2000W	240V	8.33 A
5000W	480V	10.42 A

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Formula Breakdown

🔋 DC

Amps = Watts ÷ Volts

Direct current has no phase shift. Power factor = 1 always. Common in batteries, solar, automotive, and electronics.

⚡ AC Single Phase

Amps = Watts ÷ (Volts × PF)

Standard household power. Power Factor accounts for reactive loads. Use PF=1.0 for heaters, PF=0.8 for motors.

🏭 AC Three Phase

Amps = Watts ÷ (1.732 × V × PF)

Industrial power delivery. The √3 (≈1.732) factor reflects the phase offset between the three conductors.

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Real-World Examples

Device	W / V	Amps
Car Charger	120W / 12V	10.00 A
Solar Panel	400W / 24V	16.67 A
Hair Dryer	1800W / 120V	15.00 A
Air Conditioner	2000W / 240V	10.42 A
Microwave	1000W / 120V	8.33 A
Ind. Motor	7500W / 480V	9.01 A
HVAC Unit	5000W / 240V	12.03 A

What You Need to Know About Watts, Amps & Volts

Understanding the relationship between Watts, Amps, and Volts is foundational for anyone working with electrical systems — from DIY home wiring to solar installations and industrial motor control.

🔌 What Are Amps?

Amps (amperes) measure electrical current — the rate of electron flow. Think of it as the volume of water flowing through a pipe. Wire gauge, circuit breakers, and fuse ratings are all based on amperage.

💡 What Are Watts?

Watts measure power — the rate at which energy is consumed or produced. Appliances are rated in watts. Multiply amps × volts to get watts in DC; in AC, multiply by power factor too.

⚡ What Are Volts?

Volts measure electrical pressure (EMF). Higher voltage pushes more current through the same resistance. That's why 240V circuits are more efficient for high-power loads than 120V.

🔁 Power Factor Explained

In AC circuits, reactive loads (motors, transformers) cause current and voltage to go out of phase. Power factor (0–1) measures this efficiency. Lower PF = higher current draw for the same watts.

When wiring any circuit, always calculate the amperage first, then select wire gauge and breaker size accordingly. The NEC requires that circuit conductors be rated for at least 125% of continuous loads — so multiply your calculated amps by 1.25 before sizing your overcurrent protection device.

Frequently Asked Questions

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FAQ — Watts to Amps

Divide Watts by Volts: Amps = Watts ÷ Volts (DC). For AC single-phase: Amps = Watts ÷ (Volts × Power Factor). For AC three-phase: Amps = Watts ÷ (1.732 × Volts × Power Factor). Use the calculator above for instant, accurate answers.

At 240V DC: 8.33 Amps. At 240V AC with PF=1.0: 8.33 Amps. At 240V AC with PF=0.8: 10.42 Amps. Power factor significantly affects AC current calculations — always verify your load's PF before sizing wiring.

Yes — simply multiply kilowatts by 1000 to convert to watts. For example, 5 kW = 5000 W. Then enter that value into the Watts field. The calculation logic is identical; the unit is just scaled differently.

A 20-amp breaker safely handles 16 amps of continuous load (80% NEC rule). At 120V, that's 1920 watts. At 240V, that's 3840 watts. Never run a circuit at 100% capacity — breakers trip due to heat buildup over time, even below rated current.

In a three-phase system, the three voltage phases are offset by 120° each. The √3 factor (approximately 1.732) accounts for the vector relationship between line voltage and phase voltage. It's a mathematical constant derived from the geometry of balanced three-phase power.

Most AC induction motors operate between 0.7 and 0.9 PF depending on load. Use 0.8 as a safe default if no nameplate data is available. Variable frequency drives (VFDs) can improve PF to near 0.95. Always check the motor nameplate for the specified power factor at rated load.