Watts to Amps Calculator
Convert watts to amps (or amps to watts) for DC, single-phase or three-phasecircuits. Pick a common US voltage — 120V, 208V, 240V, 277V or 480V — set the power factor for motor and compressor loads, or jump straight to a common appliance's typical wattage below.
8.33 A
A = W ÷ (V × PF) (single-phase AC)
1,000 W ÷ (120 V × PF 1) = 8.33 A
Common US appliances — amps at 120V (quick reference)
| Appliance | Typical watts | Amps at 120V |
|---|---|---|
| LED light bulb (60W-equivalent) | 15 W | 0.13 A |
| Microwave (cooking) | 1,000 W | 8.33 A |
| Toaster (2-slice) | 900 W | 7.5 A |
| Refrigerator (average running draw) | 150 W | 1.25 A |
| Window AC (8,000 BTU, 120V) | 730 W | 6.08 A |
| Central AC (3-ton, 240V) | 3,000 W | 25 A |
| Portable space heater | 1,500 W | 12.5 A |
| Hair dryer | 1,500 W | 12.5 A |
| Vacuum cleaner | 750 W | 6.25 A |
| Electric clothes dryer | 3,000 W | 25 A |
| Dishwasher | 1,800 W | 15 A |
| Electric water heater element | 4,500 W | 37.5 A |
| 50"–60" LED TV | 120 W | 1 A |
| Desktop computer | 200 W | 1.67 A |
| Ceiling fan | 60 W | 0.5 A |
Click an appliance to load its wattage into the calculator above.
Appliance wattages: Silicon Valley Power energy chart and cross-checked DOE-style ranges (see article sources). How we calculate →
How do you convert watts to amps?
For a DC circuit, current is simply power divided by voltage: A = W ÷ V. A 100W, 12V DC device draws 8.33 A.
For single-phase AC — the standard in US homes — you also divide by the power factor (PF), which accounts for motors, transformers and other reactive loads: A = W ÷ (V × PF). Most household loads (heaters, light bulbs) are close to PF 1; motors and compressors are typically PF 0.8–0.9.
For three-phase AC (common in commercial/industrial buildings), the line-to-line current is A = W ÷ (√3 × V × PF), where √3 ≈ 1.732 accounts for the phase geometry.
How many amps is 1,000 watts?
It depends entirely on the voltage: at 120V (PF 1), 1,000W draws 8.33A; at 240V, the same 1,000W draws 4.17A — half the current, because power equals voltage times current. This is exactly why 240V circuits are used for high-wattage appliances like dryers and ranges: less current means thinner wire and less heat for the same power.
Why does power factor matter for amps?
Power factor (PF) measures how efficiently a load converts electrical current into useful power. A PF below 1 means the circuit needs to carry more current than the wattage alone suggests to deliver that power — so a 1,000W motor at PF 0.8 draws more amps than a 1,000W resistive heater at PF 1. Ignoring PF on motor/compressor loads is one of the most common wire-sizing mistakes.
Three-phase vs. single-phase: why the √3?
In a balanced three-phase system, the three line currents are offset by 120°, so the relationship between line-to-line voltage and per-phase power involves the factor √3 (≈1.732) rather than a simple product. This is why the same wattage draws noticeably less current per line on a three-phase 480V industrial circuit than it would on a single-phase 240V circuit.
Frequently asked questions
How many amps is 1,500 watts at 120V?
1,500W ÷ 120V = 12.5A at power factor 1 — right at the practical limit of a standard 15A household circuit and comfortably within a 20A circuit. This is why 1,500W space heaters and hair dryers are the largest single-plug loads recommended for a 15A outlet.
How many amps does a 240V, 5,000W dryer draw?
5,000W ÷ 240V = 20.83A at PF 1 — which is why electric dryers are wired on a dedicated 30A, 240V circuit (giving headroom above the calculated draw, per standard practice).
What's the difference between amps at 120V and 240V for the same wattage?
Current is inversely proportional to voltage for a fixed wattage: doubling the voltage halves the amps. A 3,000W load draws 25A at 120V but only 12.5A at 240V — which is why high-power appliances (ranges, dryers, EV chargers, central AC) use 240V circuits to keep wire size and heat manageable.
How do you convert amps back to watts?
Multiply: W = A × V (DC or PF-adjusted AC: W = A × V × PF). A 20A, 120V circuit at PF 1 can deliver up to 2,400W; the same 20A on a 240V circuit delivers up to 4,800W. Toggle 'Amps → Watts' above to compute this directly.
Does power factor apply to a DC circuit?
No — power factor only applies to AC circuits, where voltage and current can be out of phase due to reactive (inductive/capacitive) loads. In DC, current and voltage are always in phase, so A = W ÷ V exactly, with no PF term.
Researched & verified by the Calcuris Data & Research Team. How we build and check our tools →