How to Convert kVA to Amps

Use this page as your reference to size breakers, transfer switches, inverters, and battery cables for cabins, RV builds, backup systems, and full off-grid homes.

Quick Answer

• Single-phase: A = (kVA × 1,000) ÷ V
• Three-phase: A = (kVA × 1,000) ÷ (√3 × V)

Example: A 10 kVA load at 240 V single-phase draws 10,000 ÷ 240 = 41.7 A.

You do not need power factor to convert kVA to amps. Power factor only matters when you convert kVA to kW, which is a separate step covered below.

kVA to Amps Calculator

1. Enter your kVA rating.
2. Type in your voltage.
3. Choose single-phase or three-phase. The calculator returns amps instantly using the two formulas above.

Converting an inverter's kVA rating to DC battery amps is a different calculation. Jump to the off-grid examples further down for the battery-side method.

Default presets use common US values: 120 V and 240 V for single-phase, 208 V and 480 V for three-phase.

kVA to Amps Conversion Chart

This chart uses the same formulas as the calculator, so the two never disagree. Find your kVA in the left column, then read across to your voltage.

Values are rounded to one decimal. Each row shows the same kVA converted across six voltages, so a higher voltage always gives you fewer amps.

Formulas Explained

• Single-phase system: A = (kVA × 1,000) ÷ V. A 5 kVA load at 240 V draws 5,000 ÷ 240 = 20.8 A.
• Three-phase system: A = (kVA × 1,000) ÷ (√3 × V). A 5 kVA load at 208 V draws 5,000 ÷ (1.732 × 208) = 13.9 A per phase.

The √3 (about 1.732) comes from the 120-degree phase relationship between the three windings in a three-phase supply. The three phases share the load, so each conductor carries less current than a single-phase conductor would at the same voltage.

Three-phase adds one extra divisor, √3, and nothing else.

kVA vs kW and Why the Amp Formula Uses kVA

Real power and apparent power are linked by power factor: (Kilowatts) kW = kVA × PF.

A 5 kVA generator can supply about 4 kW at a power factor of 0.8. The 5 kVA figure is the apparent power the hardware must physically carry.

Larger generators and many inverter-chargers list a kVA rating because their windings, wiring, and switchgear have to carry the full apparent current, not just the real-power portion. Smaller portable units are often rated in watts instead. Your amp conversion depends on that full current.

If you know the load's kW and power factor, you can calculate current with a kW formula that includes PF. Plugging kW into a kVA formula without PF can undercount the current.

Why kVA to Amps Conversion Matters Off-Grid

Generator sizing: Make sure your inverter-charger never draws more than the generator can supply. Convert the generator's kVA to amps, then set the charger's input current limit at or below that figure so the generator doesn't overload or trip its breaker.

Inverter DC draw: The DC amp figure on the battery side drives your battery bank capacity and your cable gauge. Undersized cable on a high-amp DC run gets hot and wastes power.

AC protection: Use the AC amp figure as an input when sizing breakers, transfer switches, and conductors on the output side of your inverter or generator. Equipment ratings, conductor ampacity, continuous-load rules, and local code also apply.

Running a cabin or an RV build? Calculate both the AC amps and the DC amps before you buy wire. On a 48 V battery bank, the DC current can be more than four times the 240 V AC current, as the worked example below shows. On a 12 V bank, the gap is far wider.

Worked Examples

• 7.5 kVA single-phase backup at 240 V: 7,500 ÷ 240 = 31.25 A. If the load qualifies as continuous under the National Electrical Code (NEC), a 125% adjustment may apply: 31.25 × 1.25 ≈ 39 A, so a 40 A breaker may be appropriate. Confirm the final breaker and conductor sizes with your electrician and local code.
• 20 kVA three-phase generator at 480 V: 20,000 ÷ (1.732 × 480) = 24.1 A per phase. Each of the three conductors carries 24.1 A.
• 5 kVA inverter on a 48 V battery bank: The DC side carries real power, so start with watts, not VA. If the inverter lists a continuous watt rating, use it. If not, this illustration assumes a 0.8 power factor: 5 kVA × 0.8 = 4 kW. Then, assuming 90% inverter efficiency, 4,000 ÷ (48 × 0.9) ≈ 93 A DC. Use the inverter's specifications for actual design.

That 93 A figure, not the AC output amps, sets your battery cable size.

Common Mistakes to Avoid

Most sizing errors come from these four mix-ups. Each one can throw your amp calculation off enough to put you on the wrong breaker or wire size.

• Treating kVA as kW. They differ by the power factor. Convert amps from kVA; size real loads from kW.
• Using the single-phase formula on a three-phase supply. Forgetting √3 overstates your current by about 73%.
• Confusing AC amps with DC battery-side amps. The inverter's AC output and its DC battery draw are two separate numbers.
• Using line-to-neutral voltage in the three-phase formula. The formula needs line-to-line voltage. On a 208 V system, use 208 V, not the 120 V line-to-neutral value. On a 480 V system, use 480 V, not 277 V.

Build Your Off-Grid System with Off-Grid Source

Once your amp numbers are right, the next step is matching them to real hardware that works together. Tell us what you're running and for how long, and we'll check that your inverter, battery bank, and charging sources line up on both the AC and DC side. If a smaller battery bank meets your runtime, we'll tell you, so there's no need to overbuy.

Pick a starting point based on how much of the system you need:

• Complete Off-Grid Solar Kits: Pre-matched kits with panels, an inverter, and battery storage for cabins, backup, and full off-grid homes. Most full-time off-grid homes land on 8 to 15 kW of solar with 20 to 40 kWh of battery storage.
• Inverter & Battery Bundle Kits: Inverters paired with compatible lithium batteries, so your inverter matches your battery bank voltage out of the box. Add panels separately, and we'll confirm they stay within your inverter or charge controller's input range.
• Solar Batteries & Energy Storage: Server rack, wall-mount, portable, and outdoor-rated lithium batteries, so you can build a bank around your DC amp numbers.

Run your loads through our Solar System Size Calculator, then request a Free Solar Proposal for a compatibility check before you buy.