power to current calculator
Convert electrical power (W) to current (A) for DC, single-phase AC, and three-phase AC. Enter power, voltage, and power factor to get accurate RMS or DC current.
three-phase current calculator
Divide voltage by power and add in the power factor; multiply voltage by 1.732 to calculate line currents in three times a three-phase circuit.
Formula & Table Summary:
DC: I = P / V
1-phase AC: I = P / (V · PF)
3-phase AC: I = P / (√3 · V_LL · PF)
Inputs: P (W), V (V), PF (0–1). Output: I (A).
apparent current calculator
Enter Power (W), Voltage (V), and Power Factor (PF) to calculate current (A) with DC, single-phase ac or three-phase ac using the correct formula.Use this calculator to use in speedily circuit sizing checks, selecting breakers, energy audits, and determining that conductors or protective devices are not overloaded. Note:in apparent power (VA) or with line-to-neutral voltage on three-phase systems multiply voltage input by powers of two; reduce formula to the order of theSIGMAS.
watts to amps calculator
| Type | P (W) | V (V) | PF | I (A) |
|---|---|---|---|---|
| DC | 1200 | 48 | 1.00 | 25.0000 |
| 1-phase | 2300 | 230 | 0.80 | 12.5000 |
| 1-phase | 5000 | 120 | 0.95 | 43.8596 |
| 3-phase | 10000 | 415 | 0.90 | 15.4578 |
| 3-phase | 50000 | 11000 | 0.85 | 3.0874 |
Frequently Asked Questions - power to current calculator:
How do I calculate current from power for DC?
Use I = P / V (amps = watts ÷ volts).
What formula for single-phase AC with power factor?
I = P / (V · PF), where PF is 0–1 (use 1 for purely resistive loads).
What about three-phase systems?
Use I = P / (√3 · V_LL · PF) where V_LL is line-to-line voltage and PF is power factor.
If I only know VA (apparent power), what do I use?
For single-phase: I = S / V. For three-phase: I = S / (√3 · V_LL).
Can current exceed power divided by phase voltage?
If PF < 1, current will be higher than P/V because real power is reduced by PF; use PF in the denominator.
What power factor should I assume if unknown?
If unknown and load is likely resistive, assume PF ≈1. For motors or inductive loads, assume PF 0.8–0.9 unless measured.
Does this include starting/inrush currents?
No. These formulas give steady-state RMS current from steady real power. Motor starting and inrush require separate transient calculations.
How to size a breaker from calculated current?
Choose next standard breaker rating above the continuous load plus apply code derating (e.g., 125% for continuous loads per many electrical codes). Verify with local rules.
Are harmonic currents included?
No. Harmonics (from non-linear loads) increase RMS current; use measurements or harmonic analysis for accurate sizing.
What voltage should I use for 3-phase Y (wye) systems?
Use line-to-line voltage (V_LL) with the √3 formula for line current. If you must use V_LN, convert or use phase formulas accordingly.
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