DC
DC Formula
Amps = (kW × 1,000) ÷ Volts
Simple division — no power factor or √3. Used for battery systems and DC equipment.
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kW to Amps Explained
What the kW to Amps Calculator Does
A kW to amps calculator answers one question: how much current does a given power draw at my voltage? The answer matters because current, not power, is what your cables, breakers, and transfer switch must physically carry. The generator's output wiring follows the same rule.
kW
Real Power
The real power your equipment consumes. It is the number stamped on motors, heaters, and nameplates.
Amps
Current
The current flowing through the wire. Determines cable cross-section, breaker rating, and conductor temperature.
Voltage & PF
The Variables
Voltage and power factor sit between kW and amps. Both change the result dramatically — a 50 kW load at 400 V draws ~90 A; at 230 V it draws >150 A.
Same Power, Different Current
A 50 kW three-phase load at 400 V draws about 90 A per phase. The same 50 kW at 230 V draws more than 150 A. Same power, nearly double the current — a completely different cable. That's why the conversion is never a fixed number: it always depends on your supply, which is precisely what this kW to amps calculator recalculates for every entry.
More Than a Simple Converter
What Makes This Tool Different
01
DC, Single & Three-Phase
Covers DC, single-phase, and three-phase (line-to-line and line-to-neutral) — with the formula shown beside every result.
02
Global Voltage Support
Supports 50 Hz and 60 Hz systems at 230/400/415/480 V presets plus custom voltage entry — valid in your country, not just one market.
03
Real Power Factor Default
Defaults to 0.8 PF, the industrial standard for generators, with a toggle for motor and resistive loads so you see how PF changes current.
04
Connection Mode — Breaker, Cable & Generator
After the amps result, returns recommended breaker size, cable guidance, and the Huali generator whose full-load current matches your load — ending in a free factory-direct quote.
kW to Amps Converter
kW to Amps Calculator: 3-Phase & Single-Phase Converter
Convert kW to amps for DC, single-phase, and three-phase systems at 50 Hz or 60 Hz. Get the current, then find the breaker, cable size, and generator that matches your load.
Convert kW to Amps
Enter your power, voltage, and power factor. The calculator returns the current in amps per phase.
0.8 for motors/generators, 1.0 for resistive loads.
Connection Mode: Breaker, Cable & Generator
Get the full installation picture: amps, breaker size, cable guidance, and the right generator for your load.
Approximate run distance for voltage drop consideration.
kW to Amps Reference
Generator kW to Amps Reference Table (Three-Phase, 0.8 PF)
This table gives the full-load current for common generator sizes at the four most common three-phase voltages. Use it to sanity-check a calculation, size a breaker, or select cable before you finalize. For any voltage or kW outside this table, run it through the kW to amps calculator above.
| Generator kW | Amps @ 230 V | Amps @ 400 V | Amps @ 415 V | Amps @ 480 V |
|---|---|---|---|---|
| 10 kW | 31 A | 18 A | 17 A | 15 A |
| 20 kW | 63 A | 36 A | 35 A | 30 A |
| 30 kW | 94 A | 54 A | 52 A | 45 A |
| 50 kW | 157 A | 90 A | 87 A | 75 A |
| 75 kW | 235 A | 135 A | 130 A | 113 A |
| 100 kW | 314 A | 180 A | 174 A | 150 A |
| 150 kW | 471 A | 271 A | 261 A | 226 A |
| 200 kW | 628 A | 361 A | 348 A | 301 A |
| 300 kW | 941 A | 541 A | 522 A | 451 A |
| 500 kW | 1,569 A | 902 A | 870 A | 752 A |
| 1,000 kW | 3,138 A | 1,804 A | 1,739 A | 1,504 A |
Values are rounded for line-to-line voltage at 0.8 power factor, the standard rating for industrial generators. Single-phase current is roughly 73% higher than three-phase at the same voltage and power factor — another reason to verify with the calculator before ordering cables.
These sizes map to our standard diesel generator range from 8 kVA to 4,000 kVA. If your project needs a size you don't see here, we offer OEM/ODM customization across the full range.
These sizes map to our standard diesel generator range from 8 kVA to 4,000 kVA. If your project needs a size you don't see here, we offer OEM/ODM customization across the full range.
kW to Amps Formula
How to Convert kW to Amps: The kW to Amps Formula
To convert kW to amps, divide the power in watts by the voltage, then divide again by the power factor for AC loads: Amps = (kW × 1,000) ÷ (Volts × Power Factor). Three-phase systems additionally divide by √3 (≈ 1.732). A 50 kW three-phase load at 415 V with a 0.8 power factor draws about 87 A per phase.
SINGLE
AC Single-Phase
Amps = (kW × 1,000) ÷ (Volts × PF)
Divide by voltage and power factor. A 10 kW heater at 230 V, PF 1.0 draws 43.5 A.
3-PHASE
AC Three-Phase (Line-to-Line)
Amps = (kW × 1,000) ÷ (√3 × Volts × PF)
A 100 kW load at 400 V, 0.8 PF draws 180 A per phase. The √3 factor is essential.
LINE-NEUTRAL
AC Three-Phase (Line-to-Neutral)
Amps = (kW × 1,000) ÷ (3 × Volts × PF)
Used for phase-to-neutral loads. Divide by 3 instead of √3. Less common but required for some systems.
60 HZ
Worked Example — 480 V, 60 Hz
A 200 kW load on a 480 V, 60 Hz three-phase supply at 0.8 PF:
Amps = (200 × 1,000) ÷ (1.732 × 480 × 0.8) = 301 A per phase
Key Takeaway
The √3 Factor — The Most Skipped Step
The √3 factor appears only in three-phase systems and is the most commonly skipped step in the whole calculation. For the same load, voltage, and power factor, three-phase current is only about 58% of single-phase current — roughly 42% less. Use the converter above to run your own numbers in either direction.
Installation Rules
From Amps to Installation: Breaker, Cable & ATS Sizing
Once you have the amps, the physical installation follows. Every rule below starts from the same input: the amps from your kW to amps conversion. Three rules govern almost every industrial hookup, drawn from the National Electrical Code (NFPA 70).
01
Continuous Loads — 125% Rule
Conductors and overcurrent devices protecting a load that runs for three hours or more must carry 125% of the full-load current. A 90 A load needs 112.5 A → rounded up to 125 A breaker.
02
Breakers Protect Cables, Not Machines
A breaker is sized to protect the cable. The cable must have an ampacity at least equal to the breaker rating after derating for ambient temperature, bundling, and distance. Long or hot runs need larger cable.
03
Generator Output — Same Rules Apply
A generator's output breaker and cables are sized from its full-load current, not its kW rating. Undersize them and you either trip under load or cook the cable inside the enclosure — the most common field installation error.
Need Help?
From Current to Safe Installation
The commercial electrical load calculator helps you total the load side of the equation. The converter above gives you the current; the engineering step that turns current into a safe installation is exactly the kind of consultation we provide free of charge.
Common Errors
5 Common kW to Amps Mistakes
In our experience, these five errors keep showing up in real-world projects. Avoid all of them and your installation will be sized correctly from the start.
Forgetting the √3 Factor
Omitting 1.732 in a three-phase calculation inflates current by 73%, so you oversize cables and breakers. Always apply it for three-phase, never for single-phase.
Using PF 1.0 for Motor Loads
Motors run at 0.7–0.85 PF. Sizing at 1.0 under-estimates current by 20–40%, which undersizes your protection. This is the dangerous direction.
Mixing Line-to-Line and Line-to-Neutral Voltage
Three-phase amps uses line-to-line voltage. Using phase voltage with the √3 formula gives a result off by √3. Always use the correct voltage.
Sizing Breakers to 100% of Full-Load Current
Continuous loads must be protected at 125%. A breaker sized exactly to the load trips under normal running conditions. Always add the 25% margin.
Ignoring Motor Starting Current
A motor draws 6–8× its full-load current on direct-on-line starting. Your breaker and generator must survive the peak, not just the running average.
Not sure your calculation is right? Our engineers will review your load list and confirm the amps, breaker, and cable before you spend anything. Talk to our engineers.
Let's talk
Get a Factory-Direct Quote
Our engineers will review your calculated amps, confirm the breaker and cable sizing, and deliver a factory-direct price — no obligation, no hidden fees. Every quote includes the generator, automatic transfer switch, and soundproofed enclosure for a complete power solution.
Frequently Ask Questions
Q: How many amps is a 50 kW three-phase generator?
A: At 415 V and 0.8 power factor, a 50 kW three-phase generator carries about 87 A per phase (50 × 1,000 ÷ (1.732 × 415 × 0.8)). At 400 V it is about 90 A; at 480 V it is about 75 A. The calculator returns the exact value for your voltage.
Q: How many amps does a 10 kW generator produce?
A: On a single-phase 230 V supply, a 10 kW load draws about 43.5 A. On a 400 V three-phase supply at 0.8 PF, the same 10 kW draws about 18 A per phase. The answer depends entirely on your phase and voltage.
Q: How do I convert watts to amps?
A: Divide the watts by the voltage: Amps = Watts ÷ Volts for DC and resistive loads, and Amps = Watts ÷ (Volts × PF) for AC loads. A 2,300 W single-phase heater at 230 V draws 10 A. This watts to amps relationship is exactly what the calculator applies when you enter your load in kW.
Q: How do I convert kW to amps?
A: Divide the power in watts by the voltage, then by the power factor for AC loads. Amps = (kW × 1,000) ÷ (Volts × PF) for single-phase, and divide again by √3 (1.732) for three-phase.
Q: How many amps is 100 kW at 400 V?
A: At 400 V three-phase and 0.8 power factor, 100 kW draws about 180 A per phase (100 × 1,000 ÷ (1.732 × 400 × 0.8)). At 415 V it is about 174 A; at 480 V it is about 150 A.
Q: How many amps does a 7.5 kW motor draw at full load?
A: At 400 V three-phase and 0.85 power factor, a 7.5 kW motor draws about 13 A per phase (7.5 × 1,000 ÷ (1.732 × 400 × 0.85)). Full-load motor current is also published in code tables, such as NEC Article 430, based on horsepower rating.
Q: Does power factor affect the amps?
A: Yes, directly. Lower power factor means higher current for the same kW. A 100 kW load at PF 1.0 draws 144 A at 400 V three-phase; at PF 0.8 it draws 180 A. Never size cables or breakers without using the real power factor.
Q: What size breaker do I need for a 50 kW generator?
A: A 50 kW generator at 400 V three-phase outputs about 90 A per phase. Applying the 125% continuous-load rule, the breaker should be rated at 90 × 1.25 = 112.5 A, so the next standard size up, 125 A. Our engineers confirm this with your cable run and installation conditions.