How do I convert kVA to watts

In order to convert the current (in amps [A]) into real power (in watts [W]) and apparent power (in volt-amps [VA], you need to know the voltage of the network.
 
The tables below provide a quick amperage conversion.
 
Attention: we use cos φ = 0.8 here. If you are dealing with a different cos φ, you can use the formula for calculating the active power.
 
Single phase:
I [A]U = 115VU = 230V
Psingle phase [W]S.single phase [VA]Psingle phase [W]S.single phase [VA]
0.19.211.518.423
0.252328.754657.5
0.54657.592115
0.756986.25138172.5
192115184230
1.25115143.75230287.5
1.5138172.5276345
1.75161201.25322402.5
2184230368460
2.25207258.75414517.5
2.5230287.5460575
2.75253316.25506632.5
3276345552690
3.25299373.75598747.5
3.5322402.5644805
3.75345431.25690862.5
4368460736920
 
Used formulas:
  • Psingle phase = U * I * cos φ
  • S.single phase = U * I
 
Three-phase:
I [A]U = 230VU = 400V
Pthree phase [W]S.three phase [VA]Pthree phase [W]S.three phase [VA]
0.131.8739.8455.4369.28
0.2579.6799.59138.56173.21
0.5159.35199.19277.13346.41
0.75239.02298.78415.69519.62
1318.70398.37554.26692.82
1.25398.37497.96692.82866.03
1.5478.05597.56831.381039.23
1.75557.72697.15969.951212.44
2637.39796.741108.511385.64
2.25717.07896.341247.081558.85
2.5796.74995.931385.641732.05
2.75876.421095.521524.201905.26
3956.091195.111662.772078.46
3.251035.771294.711801.332251.67
3.51115.441394.301939.902424.87
3.751195.111493.892078.462598.08
41274.791593.492217.022771.28
 
Used formulas:
  • Pthree phase = U * I * cos φ * √3
  • S.three phase = U * I * √3
 
When we need to determine the performance of a load, we first see whether this load is single-phase or three-phase.
The real power P (in watts) is equal to the voltage U (in volts) times the current I (in amperes) and the cos φ.
Psingle-phase> = U * I * cos φ [W]
 
The apparent power S (in volt amperes) is equal to the voltage U (in volts) times the current I (in amperes).
S.single-phase = U * I [VA
The real power P (in watts) is equal to the voltage U (in volts) times the current I (in amperes), the cos φ and the concatenation factor √3.
Pthree-phase = U * I * cos φ * √3 [W]
 
The apparent power S (in volt amperes) is equal to the voltage U (in volts) times the current I (in amperes) and the concatenation factor √3.
S.three-phase = U * I * √3 [VA]
 
If we now want to convert the active power P in watts (W) into apparent power S in volt amperes (VA), we apply the following formula:
S.three phase= Pthree phase/ cos φ