Quick, accurate electrical conversions with European voltages as the default. Every tool supports single-phase, three-phase and DC where it applies, and shows its working.
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Most online converters assume a 120 V American supply. The UK and the rest of Europe use 230 V single-phase and 400 V three-phase, so results from those tools can be badly wrong here. These calculators start at 230 V and 400 V and still offer 120 V and 240 V when you need them.
Conversions are for planning and understanding only. Choosing cables, fuses and breakers must be done by a qualified electrician, and fixed installations in the UK must meet BS 7671.
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Frequently Asked Questions
How many amps is 3 kW at 230 V?
At 230 V and a power factor of 1, 3 kW draws about 13 A, because current equals power divided by voltage. On a 400 V three-phase supply the same 3 kW draws about 4.3 A per line.
What is the difference between kW and kVA?
kW is real power that does useful work, while kVA is apparent power, the product of voltage and current. They are linked by the power factor: kW equals kVA times power factor. For a heater they are almost equal; for motors kVA is higher.
Which voltage should I use for calculations in Europe?
Use 230 V for single-phase and 400 V line to line for three-phase supplies in the UK and EU. These are the harmonised nominal values, and real voltages vary slightly around them.
Checked October 2026 by the Solaxyra Editorial Team. Read how we build and check our tools in our editorial policy.