Quick Answer: Amps to Watts
One amp equals 230 watts at 230 V (1 A = 230 W).
Conversely, 1 W ≈ 0.004348 A at 230 V.
Formula: W = A × 230 V
Worked examples
- 1 A = 230 W at 230 V
- 2 A = 460 W at 230 V
- 5 A = 1,150 W at 230 V
Method and limitations
For DC, P = I × V. For single-phase AC, V × I gives apparent power in VA; real power in watts is P = V × I × PF. For balanced three-phase AC, P = √3 × V_L × I × PF. The calculator multiplies by the voltage you select, so on AC it gives watts only when PF = 1 and VA otherwise. Calculations use full-precision constants; answers in this box are rounded for readability (≈ marks a rounded value) and the calculator shows up to 9 significant figures. This is not a fixed unit pair: the result uses 230 V and assumes DC or single-phase AC with a power factor of 1. AC loads with a lower power factor, and three-phase supplies, need the formulas shown further down the page.
Each factor is exact by definition, derived from exact definitions, or a documented conventional value — see the methodology and sources.
Conversion Formula
For DC, P = I × V. For single-phase AC, V × I gives apparent power in VA; real power in watts is P = V × I × PF. For balanced three-phase AC, P = √3 × V_L × I × PF. The calculator multiplies by the voltage you select, so on AC it gives watts only when PF = 1 and VA otherwise.
This formula uses the supply voltage currently set in the calculator (230 V). Change it above and this formula updates with it — the relationship is not a fixed unit pair.
When amps × volts is watts — and when it is not
For DC, watts = amps × volts. On AC, amps × volts is apparent power in VA; real power in watts is V × I × PF. A clamp-meter reading of 5 A on a 230 V motor circuit is 1,150 VA, which is 1,150 W only if the power factor is 1. Balanced three-phase uses P = √3 × VL × I × PF.
A circuit or fuse rating in amps converted to watts is not a statement of what that circuit can safely supply continuously; that depends on the installation and local rules.
Once you know a device's power, the home energy audit calculator turns it into kWh and cost with your own tariff; see the Home Energy guide.
Constants and their sources are listed on the methodology page.
Complete Guide to Amps to Watts Conversion
What is an amp?
The ampere (A) is the SI unit of electric current. Fuses, breakers, chargers and supplies are often rated in amps.
What is a watt?
The watt (W) is the SI unit of real power. On AC it differs from volt-amperes (VA, apparent power) by the power factor.
How the Conversion Works
Multiply current by voltage: that is watts for DC and VA for AC. Multiply by power factor for real power on AC, and by √3 (with line-to-line voltage) for balanced three-phase.
Why This Conversion Matters
Current ratings are common on supplies and protective devices; power ratings are common on loads. Converting between them correctly needs voltage, power factor and phase stated explicitly.
Scientific Context
P = V × I × cos φ for sinusoidal single-phase AC, where cos φ is the displacement power factor. Non-linear loads also have harmonic distortion, which is why the datasheet power factor is the figure to use.
Step-by-Step Conversion Guide
Follow these steps to convert amps to watts manually:
Start with your value in amps
Example: You want to convert 5 A
Apply the conversion formula
Use the formula: W = A × 230 V
Calculate the result
5 A = 1,150 W
Verify your answer
Use our calculator above to double-check your manual calculation.
Quick Mental Math Tip
At 230 V each amp is 230 W (or VA); at 120 V, 120 W; at 12 V DC, 12 W. So 10 A at 230 V ≈ 2.3 kW.
Common Conversions
Calculated at 230 V (supply voltage). Change the value in the calculator above and this table recalculates.
| Amps (A) | Watts (W) | Watts → Amps |
|---|---|---|
| 1 A | 230 | 1 W = 0.00434783 A |
| 2 A | 460 | 2 W = 0.00869565 A |
| 5 A | 1,150 | 5 W = 0.0217391 A |
| 6 A | 1,380 | 6 W = 0.026087 A |
| 10 A | 2,300 | 10 W = 0.0434783 A |
| 13 A | 2,990 | 13 W = 0.0565217 A |
| 16 A | 3,680 | 16 W = 0.0695652 A |
| 20 A | 4,600 | 20 W = 0.0869565 A |
| 32 A | 7,360 | 32 W = 0.13913 A |
| 40 A | 9,200 | 40 W = 0.173913 A |
When You'll Need This Conversion
Clamp-meter readings
Turn a measured current into approximate power at a known voltage, remembering power factor on AC.
DC accessories
Find the power of a 12 V or 24 V device from its fuse or current rating.
Rating plates in amps
Express a device or supply rating given in amps as VA or W at its stated voltage.
Pro Tips for Accurate Conversions
Say VA when PF is unknown
Amps × volts on AC is an upper bound for watts, reached only at PF = 1.
Measure, do not guess, PF
Use the datasheet or an energy meter that reports power factor.
Common Mistakes to Avoid
Treating W = A × V as universal
It holds for DC and resistive AC loads, not for loads with PF < 1 or three-phase supplies.
Use P = V × I × PF, or √3 × V_L × I × PF for three-phase.
Reading circuit ratings as safe continuous loads
Local rules may limit continuous loading below the protective-device rating.
Ask a qualified electrician for installation limits.
Frequently Asked Questions
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Conversion factors on this page are either exact by definition, derived from exact definitions, or conventional values in documented use. Each is listed with its source in our conversion methodology and sources, which cites the BIPM SI Brochure, NIST Special Publication 811 and the relevant IEC or national standards. Results are rounded for display only; calculations use full precision.