Convert apparent power into current for single-phase and three-phase systems. Use line-to-line or line-to-neutral voltage, review the formula, and check real-world sizing examples before you install.
Enter electrical parameters to see amperage results
This kVA to amps calculator helps you estimate current draw from an apparent power rating, which is the value most often shown on a transformer, generator, UPS, or piece of industrial equipment. The tool is simple, but the quality of your result depends on choosing the right system type and voltage reference before you click calculate.
Type the apparent power from the equipment nameplate. Common examples are 15 kVA control transformers, 45 kVA dry-type transformers, and 100 kVA generators.
Use single-phase for typical residential and light commercial loads. Use three-phase for larger motors, panels, distribution gear, and most industrial service equipment.
Match the voltage to the system. For three-phase systems, choose line-to-line when the nameplate shows 208V, 400V, or 480V. Choose line-to-neutral only if that is the value you actually have.
Use the amps result as a load current estimate. Then confirm wire ampacity, overcurrent protection, voltage drop, and local code rules before you install or specify equipment.
You will most often use a kVA to amps calculator when the nameplate gives you apparent power but you still need current draw for branch circuit planning. That happens all the time with transformers, generators, UPS systems, VFD-fed equipment, and service entrance studies. Instead of manually rearranging the formula every time, you can confirm the load in a few seconds and move on to conductor sizing or breaker selection.
The most common mistake is choosing the wrong voltage basis. That is why this page explains both line-to-line voltage and line-to-neutral voltage in plain language. If you match the nameplate value and use the correct phase selection, the result is a strong starting point for electrical design, estimating, and job site troubleshooting.
Your main result is current in amperes, but the supporting values also help you understand the load, compare equipment ratings, and avoid mixing apparent power with real power.
The amps result shows the current draw that matches the kVA and voltage you entered. This is the number electricians compare against conductor ampacity, disconnect ratings, and overcurrent protection. Higher current draw usually means larger conductors, larger protective devices, and more attention to voltage drop.
Treat the output as a load-current estimate, not the final installation answer. Starting current, continuous-load rules, harmonics, duty cycle, and ambient temperature can all change what you need in the field.
kVA is apparent power, while kW is real power. Apparent power tells you the total demand seen by the source. Real power tells you how much of that demand is doing useful work. Because this calculator starts with kVA, the amps result is based on apparent power and voltage. Power factor matters when you convert kVA to kW, but it does not change the core kVA-to-amps relationship.
If you are using this result in the United States, remember that the NEC often requires continuous loads to be treated at 125 percent for conductor or overcurrent device sizing. The calculator gives you current first, then you apply the code rules that fit the job.
Apparent power is measured in kilovolt-amperes and represents the total power a source must supply to an AC load.
Current draw is the amperage flowing through the circuit. This value helps with branch circuit design, conductor size, and overcurrent protection.
A single-phase system is common in homes and smaller loads. The current formula is direct because there is only one alternating phase relationship.
A three-phase system spreads load over three waveforms. It is common in commercial and industrial power distribution because it supports larger equipment efficiently.
Power factor is the ratio of real power to apparent power. It is useful for kVA-to-kW conversion, energy studies, and motor performance checks.
Overcurrent protection includes breakers and fuses that open the circuit when current exceeds safe limits for the equipment or conductor.
If you want to calculate amps from kVA manually, the key is to use the correct formula for the system type and the correct voltage reference for the circuit.
Use this when the load is supplied by a single-phase source:
I = (kVA x 1000) / V
Example: A 25 kVA single-phase load at 240V draws 104.17 amps. You get that by multiplying 25 by 1,000 and dividing by 240.
Use this for balanced three-phase systems when the voltage is listed phase-to-phase:
I = (kVA x 1000) / (1.732 x VLL)
Example: A 100 kVA load at 480V three phase draws about 120.28 amps. This is one of the most common transformer and generator sizing checks in North American facilities.
Use this if the voltage you have is phase-to-neutral:
I = (kVA x 1000) / (3 x VLN)
This form gives the same answer as the line-to-line version when the values describe the same balanced system. It simply matches a different way of expressing the voltage.
Suppose you are checking a 45 kVA dry-type transformer on a 208V three-phase panel. You know the transformer rating in kVA, and you need current to estimate feeder size and protective devices. The manual calculation is:
I = (45 x 1000) / (1.732 x 208) = 124.9 amps
That 124.9-amp result is your load current estimate. If the load is continuous, you may then need to size conductors or a breaker above that value based on code. This is why a current calculation and a final protective-device decision are related, but not the same step.
Many people search for a three-phase kVA to amps formula and then wonder whether power factor belongs in the denominator. It does not when you start with kVA. kVA already includes the effect of reactive and real power together. That is why this calculator uses power factor only for the supporting kW and kVAR figures.
If you started with kW instead of kVA, power factor would matter because you would first need to convert real power to apparent power. This distinction is one of the biggest points of confusion in electrical estimating, so it is worth getting right.
These examples show how the conversion appears in real estimating, maintenance, and design work.
A 15 kVA single-phase load at 240V draws 62.5 amps. This kind of check is useful when you are reviewing subpanels, HVAC equipment, or backup power tie-ins in a home or small shop.
A 60 kVA generator at 480V three phase supplies about 72.17 amps. That lets you compare the generator rating with feeder current, ATS ratings, and the expected current draw of connected loads.
A 75 kVA transformer with a 208V three-phase secondary delivers about 208.2 amps. This is a classic transformer sizing question and a common reason people search for a line-to-line kVA to amps calculator.
A 30 kVA UPS at 208V three phase draws about 83.3 amps. That value helps you review bypass devices, battery cabinets, and the branch circuit current feeding the UPS input.
If the equipment documentation gives you 10 kVA at 400V three phase, the current is about 14.43 amps. That is a practical check before you move into starter selection, conductor sizing, or voltage drop review.
If a calculated load runs for three hours or more, do not stop at the raw amps value. In many U.S. installations, you still need to apply the 125 percent rule for continuous loads before choosing conductors or overcurrent protection.
This is the biggest content gap on many competing pages and the most common source of calculation mistakes in the field.
Use line-to-line voltage when the equipment rating is shown phase-to-phase. Common examples are 208V, 230V, 400V, and 480V on three-phase panels, motors, generators, and transformers. In those cases, the familiar formula is:
I = (kVA x 1000) / (1.732 x VLL)
If you use line-to-neutral by accident when the nameplate is line-to-line, you will overstate the current and may choose the wrong equipment size.
Use line-to-neutral voltage only when the available data is phase-to-neutral, such as 120V on a 208Y/120V system or 277V on a 480Y/277V system. In that case, use:
I = (kVA x 1000) / (3 x VLN)
These two formulas describe the same balanced three-phase physics. They simply start with a different voltage reference, so the math is arranged differently.
If a generator, transformer, or panel says 480V three phase, that is usually line-to-line. If a document says 277V phase to neutral on a 480Y/277V system, that is line-to-neutral. Matching the formula to that description keeps your current draw estimate aligned with the equipment data and prevents confusion later in the design process.
This distinction matters for transformer sizing, generator sizing, branch circuit calculations, and load studies. It is also one of the easiest ways to tell whether a published conversion chart applies to your actual system.
Keep your electrical workflow moving with related LiteCalc tools for voltage drop, power, and circuit analysis.
Check voltage drop across conductors after you estimate current draw so you can choose wire runs that perform safely over distance.
Calculate electrical load, energy use, and cost after you convert apparent power into current for the circuit.
Move from current estimates into voltage, resistance, and power checks for branch circuits and troubleshooting.
Review temperature values when ambient conditions or equipment heat affect conductor ampacity or enclosure planning.
Convert related electrical units when you need to move between kW, watts, volts, and other engineering values during project review.
Estimate real power after you review current draw, power factor, and operating voltage for the same equipment set.
Quick answers to the kVA to amps questions people ask most often.
For a single-phase system, divide kVA times 1,000 by voltage. For a balanced three-phase system using line-to-line voltage, divide kVA times 1,000 by 1.732 times voltage. If you are given line-to-neutral voltage in a three-phase system, divide by 3 times voltage.
The standard balanced-load formula is I = (kVA x 1000) / (sqrt(3) x VLL). If your three-phase voltage is line-to-neutral instead of line-to-line, use I = (kVA x 1000) / (3 x VLN).
Use the same voltage reference that matches your system data. Most three-phase equipment nameplates list line-to-line voltage such as 208V, 400V, or 480V. If you only know the phase-to-neutral value, use the line-to-neutral option so the formula stays correct.
Not in a pure kVA-to-amps conversion. kVA is apparent power, so the current comes from apparent power and voltage alone. Power factor matters when you convert kVA to kW or when you estimate real power demand.
In a single-phase circuit, 25 kVA at 240V is about 104.17 amps because 25 x 1000 / 240 = 104.17.
At 480V three phase using line-to-line voltage, the current is about 120.28 amps because 100 x 1000 / (1.732 x 480) = 120.28.
Yes. Generator, transformer, and UPS ratings are often shown in kVA, while conductors and protective devices are sized by current. This conversion gives you the running current, but you should still check nameplate data, duty cycle, ambient conditions, and code rules.
The calculator gives you load current, not the final breaker size. Breaker selection depends on equipment type, continuous-load rules, inrush current, conductor ampacity, and your local code. In the U.S., continuous loads are often sized at 125 percent under NEC rules.
A continuous load can run for three hours or more, so U.S. code commonly requires extra capacity to limit overheating and nuisance trips. For example, a 100-amp continuous load is often treated as 125 amps for conductor or overcurrent device sizing, depending on the installation rules that apply.