Quick Answer: Watts to Amps
One watt is approximately 0.004348 amps at 230 V (1 W ≈ 0.004348 A).
Conversely, 1 A = 230 W at 230 V.
Formula: A = W ÷ 230 V
Worked examples
- 100 W ≈ 0.4348 A at 230 V
- 500 W ≈ 2.174 A at 230 V
- 1000 W ≈ 4.348 A at 230 V
Method and limitations
Current depends on voltage, so this calculator asks for it. For DC, and for single-phase AC with a power factor of 1, I = P ÷ V. For single-phase AC with power factor PF, I = P ÷ (V × PF). For balanced three-phase AC with line-to-line voltage V_L, I = P ÷ (√3 × V_L × PF). The calculator applies the first formula at the voltage you select. 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
Current depends on voltage, so this calculator asks for it. For DC, and for single-phase AC with a power factor of 1, I = P ÷ V. For single-phase AC with power factor PF, I = P ÷ (V × PF). For balanced three-phase AC with line-to-line voltage V_L, I = P ÷ (√3 × V_L × PF). The calculator applies the first formula at the voltage you select.
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.
Voltage, power factor and phase
The calculator applies I = P ÷ V at the voltage you select. That is exact for DC and for single-phase AC loads with a power factor of 1 (heaters, kettles). For other AC loads use I = P ÷ (V × PF), and for balanced three-phase I = P ÷ (√3 × VL × PF), with the power factor from the datasheet.
The result is a calculation input, not electrical design. Breakers, sockets and cables are selected under local wiring rules that also consider continuous load, cable length, installation method and inrush current — have fixed wiring designed and checked by a qualified electrician.
To turn a load's power into energy and cost, use the home energy audit calculator or the standby power audit; the Home Energy guide explains the next steps.
Constants and their sources are listed on the methodology page.
Complete Guide to Watts to Amps Conversion
What is a watt?
The watt (W) is the SI unit of power, one joule per second. On an AC nameplate it is normally real power.
What is an amp?
The ampere (A) is the SI unit of electric current. It is the quantity that heats conductors, which is why it matters for electrical design.
How the Conversion Works
P = V × I × PF for single-phase AC (PF = 1 for DC and purely resistive loads), so I = P ÷ (V × PF). Three-phase adds √3 with line-to-line voltage. This page computes I = P ÷ V; apply PF and √3 yourself where they apply.
Why This Conversion Matters
A power figure alone does not determine current. Voltage, power factor and phase arrangement all change the answer, and the answer is an input to — not a substitute for — electrical design.
Scientific Context
Apparent power S (VA) = V × I. Real power P (W) = S × PF. For resistive loads such as heaters, PF is close to 1; for motors and electronics it can be lower and is stated on the datasheet.
Step-by-Step Conversion Guide
Follow these steps to convert watts to amps manually:
Start with your value in watts
Example: You want to convert 1000 W
Apply the conversion formula
Use the formula: A = W ÷ 230 V
Calculate the result
1000 W = 4.3478 A
Verify your answer
Use our calculator above to double-check your manual calculation.
Quick Mental Math Tip
At 230 V each kilowatt is about 4.35 A; at 120 V about 8.3 A; at 12 V DC about 83 A.
Common Conversions
Calculated at 230 V (supply voltage). Change the value in the calculator above and this table recalculates.
| Watts (W) | Amps (A) | Amps → Watts |
|---|---|---|
| 100 W | 0.434783 | 100 A = 23,000 W |
| 500 W | 2.17391 | 500 A = 115,000 W |
| 1000 W | 4.34783 | 1000 A = 230,000 W |
| 1500 W | 6.52174 | 1500 A = 345,000 W |
| 2000 W | 8.69565 | 2000 A = 460,000 W |
| 2200 W | 9.56522 | 2200 A = 506,000 W |
| 3000 W | 13.0435 | 3000 A = 690,000 W |
| 3680 W | 16 | 3680 A = 846,400 W |
| 7400 W | 32.1739 | 7400 A = 1,702,000 W |
| 11000 W | 47.8261 | 11000 A = 2,530,000 W |
When You'll Need This Conversion
Reading an appliance nameplate
Turn a rated power in W into the current it draws at your supply voltage.
DC systems
Check current in 12 V or 48 V systems, where low voltage means high current for the same power.
Input to an electrician's design
Provide an estimated current figure; the installation itself is sized under local rules.
Pro Tips for Accurate Conversions
Use the voltage at the load
Nominal voltages (230 V, 120 V, 12 V) are fine for estimates; measured voltage varies.
Real power vs apparent power
W is real power. VA is apparent power = W ÷ PF. Current follows apparent power.
Common Mistakes to Avoid
Assuming a voltage without saying so
The same 2,000 W is 8.7 A at 230 V but 16.7 A at 120 V.
Always quote the voltage with the current.
Using single-phase formulas on three-phase supplies
Dividing by 400 V alone understates per-line current by a factor of √3.
Use I = P ÷ (√3 × V_L × PF).
Ignoring power factor on motors
Inductive loads draw more current than P ÷ V suggests.
Divide additionally by the stated power factor.
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.