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Home › Electrical Calculators › Electrical Power Calculator

Power Calculator

Enter the electrical values below to calculate the result.

The electrical potential in volts (V).
The electrical current in amperes (A).
Select whether the system is DC, AC Single-Phase, or AC Three-Phase.
The ratio of real power to apparent power (efficiency, 0.8 is typical).
Calculation Formula
Watts = Volts × Amps × PF × Phase Mult
Calculates active electrical power. Phase Multipliers: DC = 1, AC 1-Phase = 1, AC 3-Phase Line-to-Line = 1.732, AC 3-Phase Line-to-Neutral = 3.

Calculated Result

0.00 W

Calculated real power in Watts (W).

Calculation Breakdown

DETAILED PARAMETER OVERVIEW

Parameter Value
Calculated Value 0.00 W

ℹ️ About Power Calculator Calculator

The Power Calculator Calculator converts V/I/R to Watts instantly and accurately. Whether you're sizing electrical equipment, designing circuits, or checking power requirements, this tool gives you fast, reliable results.

📋 How to Use

  1. Enter the value in V/I/R.
  2. Enter any other required values (voltage, power factor, etc.).
  3. Click Calculate to convert to Watts.
  4. Read the result and use the formula shown for manual verification.

🔢 Formula / Calculation Method

P = V × I | P = I² × R | P = V² ÷ R

Enter any two known values to find power in watts.

👥 Who Uses It

  • Electricians
  • Engineers
  • Students
  • Hobbyists
  • Technicians

📌 Practical Examples

V/I/R Input
Enter V/I/R value and required parameters.
Result
Instantly see the equivalent Watts value.
Circuit Sizing
Use the result to size wires, breakers, or equipment.
Verification
Cross-check manual calculations.

⭐ Benefits

⚡
Fast
Instant conversion results
🎯
Accurate
Industry-standard formulas
📱
Mobile
Works on any device
🔢
Formula
See the math behind results
🆓
Free
No cost or login
🌍
Universal
Works for any voltage system

💡 Tips

  • 💡Always enter the correct voltage (120V, 220V, 240V, 480V etc.) for your system.
  • 💡For 3-phase systems, use the 3-phase formula option if available.
  • 💡Power factor is typically 0.8–0.95 — use 0.85 if unsure.
  • 💡Always verify calculated values against local electrical codes (NEC, IEC).

❓ Frequently Asked Questions

How do I convert V/I/R to Watts?
Use the formula: P = V × I | P = I² × R | P = V² ÷ R
What voltage should I use?
Use your system voltage — 120V or 240V for US residential, 230V for UK/EU.
What is power factor?
Power factor (0–1) represents how efficiently power is used. Use 0.8 as a safe default.
Is the calculator accurate?
Yes, it uses standard electrical engineering formulas.
Is it free?
Yes, completely free.
Should I rely on this for wiring?
Always verify with a licensed electrician before making wiring decisions.
Does it support 3-phase?
Yes, select the 3-phase option if your system uses three-phase power.
What is the difference between kVA and kW?
kW is real power; kVA is apparent power. kW = kVA × Power Factor.

🔗 Related Calculators

⚡Ohm's Law ⚡Power Calculator ⚡Voltage Drop ⚡Amps to Watts ⚡Watts to kWh ⚡Wire Gauge

🚀 Features

⚡
Instant Results
Calculate in seconds, no waiting
🎯
High Accuracy
Precise results every time
📱
Mobile Friendly
Works on any device or screen size
🔒
Privacy First
No data stored or shared
🌍
Works Worldwide
Available 24/7 from anywhere
🆓
100% Free
Always free, no registration needed

⚠️ Common Mistakes to Avoid

  • ⚠️Using the wrong voltage (120V vs 240V) — this halves or doubles results.
  • ⚠️Ignoring power factor for AC circuits — can cause undersized equipment.
  • ⚠️Confusing single-phase and three-phase formulas.
  • ⚠️Using DC formulas for AC circuits without power factor adjustment.

📖 Glossary

Volt (V)
Unit of electrical potential — the 'pressure' that drives current.
Ampere (A)
Unit of electrical current — the 'flow rate' of electrons.
Watt (W)
Unit of real power — energy per unit time.
kVA
Kilo-Volt-Amperes — unit of apparent power in AC systems.
Power Factor
Ratio of real power to apparent power (0 to 1).
kWh
Kilowatt-hour — unit of energy consumed over time.

📢 Disclaimer

Electrical calculations are provided for reference only. Always consult a licensed electrician and verify against local electrical codes before making wiring or equipment decisions.

About Power Calculator

Our electrical power calculator computes active power in Watts. This is the rate at which electrical energy is converted into another form of energy like heat, light, or mechanical force.