Amp to kW rating
Turn a current rating into the kW and kVA ratings you would find on an equipment nameplate.
Inputs
Rating plate
How amp to kW rating calculator works
The amp to kW rating calculator converts a current rating into kilowatt (kW) and kilovolt-ampere (kVA) ratings with 4 inputs: current, voltage, phase and power factor. The nameplate view lists supply, voltage, current, kW, kVA and power factor.
kVA = I × V / 1000 · kW = kVA × PFA 20 A rating at 230 V and PF 0.8 gives 4.6 kVA and 3.68 kW.
Amp to kW rating formula
The amp to kW rating formula is kW = I × V × PF / 1,000. There are 3 rating formulas: kVA rating, kW rating and three-phase kVA rating.
kVA rating
kVA = I × V / 100020 A × 230 V / 1,000 = 4.6 kVA
kW rating
kW = kVA × PF4.6 kVA × 0.8 = 3.68 kW
Three-phase kVA
kVA = √3 × I × V / 10001.732 × 100 A × 400 V / 1,000 = 69.28 kVA
4 equipment types carry kVA ratings: transformers, generators, uninterruptible power supplies (UPS) and alternators. Heaters, motors and appliances carry kW ratings.
Amp to kW rating conversion chart
The amp to kW rating conversion chart lists 11 current ratings from 5 A to 200 A with kVA and kW (PF 0.8) at 230 V single phase and 400 V three phase.
| Amps | 230 VkVA | 230 VkW @0.8 | 400 V 3φkVA | 400 V 3φkW @0.8 |
|---|---|---|---|---|
| 5 A | 1.15 | 0.92 | 3.46 | 2.77 |
| 10 A | 2.3 | 1.84 | 6.93 | 5.54 |
| 13 A | 2.99 | 2.39 | 9.01 | 7.21 |
| 16 A | 3.68 | 2.94 | 11.09 | 8.87 |
| 20 A | 4.6 | 3.68 | 13.86 | 11.09 |
| 32 A | 7.36 | 5.89 | 22.17 | 17.74 |
| 40 A | 9.2 | 7.36 | 27.71 | 22.17 |
| 63 A | 14.49 | 11.59 | 43.65 | 34.92 |
| 100 A | 23 | 18.4 | 69.28 | 55.43 |
| 125 A | 28.75 | 23 | 86.6 | 69.28 |
| 200 A | 46 | 36.8 | 138.56 | 110.85 |
A 63 A three-phase rating at 400 V is 43.65 kVA and 34.92 kW at PF 0.8.
Amp to kW rating Excel formula
The amp to kW rating Excel formula is =A2*B2*C2/1000 with the amp rating in A2, volts in B2 and power factor in C2. Use =A2*B2/1000 for the kVA rating.
| A | B | C | D | E | |
|---|---|---|---|---|---|
| 1 | Amps | Volts | PF | kW | Formula in D |
| 2 | 20 | 230 | 0.8 | 3.68 | =ROUND(A2*B2*C2/1000,2) |
| 3 | 100 | 400 | 0.8 | 55.43 | =ROUND(SQRT(3)*A3*B3*C3/1000,2) |
| 4 | 30 | 240 | 1 | 7.2 | =ROUND(A4*B4*C4/1000,2) |
Add =A2*B2/1000 in column E for the kVA rating of single-phase rows.
Amp to kW rating equation
The amp to kW rating equation is kW = kVA × PF, where kVA = I × V / 1,000 for single phase.
- kW
- Real power rating
- I
- Current rating in amperes (A)
- V
- Rated voltage (V)
- PF
- Power factor; kW equals kVA at PF 1
A kVA rating is always equal to or higher than the kW rating for the same equipment.
Amp to kW rating FAQ
What is the kW rating of a 20 amp circuit?
A 20 amp circuit is rated 4.6 kW at 230 V, 4.8 kW at 240 V and 2.4 kW at 120 V, at a power factor of 1.
How do I convert a kVA rating to kW?
To convert a kVA rating to kW, multiply kVA by the power factor: 10 kVA × 0.8 = 8 kW.
What does the amp rating on a nameplate mean?
The amp rating on a nameplate is the full-load current the equipment draws at rated voltage and output. Breakers and cables are sized from this value.
Is a kVA rating higher than a kW rating?
Yes, a kVA rating is equal to or higher than a kW rating. The 2 ratings match only at a power factor of 1.