Free to Use

Electrical Calculator

Professional electrical engineering calculations for voltage, current, resistance, power, and more. Solve Ohm's law, power calculations, and electrical circuits with precision.

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Voltage (V)
0 V
Electrical potential
Current (I)
0 A
Electric current
Resistance (R)
0 Ω
Electrical resistance
Power (P)
0 W
Electrical power
Power (P = V × I)
0 W
Voltage × Current
Power (P = V²/R)
0 W
Voltage squared / Resistance
Power (P = I²R)
0 W
Current squared × Resistance
Energy (1 hour)
0 Wh
Power × 1 hour
Resistance
0 Ω
R = ρL/A
Conductance
0 S
G = 1/R
Resistance at Temp
0 Ω
Temperature adjusted
Power Dissipation
0 W/m³
Power density
Energy Stored
0 J
E = ½CV²
Charge Stored
0 C
Q = CV
Reactance (Xc)
0 Ω
Xc = 1/(2πfC)
RC Time Constant
0 s
τ = RC

⚡ Electrical Calculator Features

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Ohm's Law Calculations
Calculate voltage, current, and resistance using Ohm's law. Find any missing value when two are known.
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Power Calculations
Determine electrical power using multiple formulas: P=VI, P=V²/R, P=I²R. Calculate energy consumption.
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Resistance Analysis
Calculate resistance from material properties, temperature effects, and conductance relationships.
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Capacitance Calculations
Calculate energy storage, charge, reactance, and time constants for capacitive circuits.
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Circuit Analysis
Analyze AC and DC circuits with comprehensive electrical parameter calculations.
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Engineering Precision
Professional-grade calculations with high precision for engineering and educational applications.

📚 How to Use the Electrical Calculator

🔌 Ohm's Law Calculator

Use Ohm's law to find voltage, current, or resistance when two values are known. Simply enter any two values, and the calculator will determine the third automatically.

Example: If you have a 12V battery and a 100Ω resistor, enter these values to find the current: I = V/R = 12V/100Ω = 0.12A

⚡ Power Calculator

Calculate electrical power using different combinations of voltage, current, and resistance. The calculator shows all possible power calculations simultaneously.

Example: For a 120V circuit with 10A current, power = V × I = 120V × 10A = 1200W (1.2kW)

🔧 Resistance Calculator

Determine resistance based on material properties including resistivity, length, cross-sectional area, and temperature effects.

Example: For a copper wire (ρ = 1.68×10⁻⁸ Ω⋅m), 10m long, 1mm² area: R = ρL/A = 0.168Ω

🔋 Capacitance Calculator

Calculate energy storage, charge capacity, and AC circuit properties for capacitors in electrical systems.

Example: A 100µF capacitor at 12V stores energy: E = ½CV² = ½ × 100×10⁻⁶ × 12² = 7.2mJ

📐 Essential Electrical Formulas

Ohm's Law
V = I × R
Where:
V = Voltage (volts)
I = Current (amperes)
R = Resistance (ohms)
Electrical Power
P = V × I = V²/R = I²R
Where:
P = Power (watts)
V = Voltage (volts)
I = Current (amperes)
R = Resistance (ohms)
Resistance from Material Properties
R = ρL/A
Where:
R = Resistance (ohms)
ρ = Resistivity (ohm⋅meters)
L = Length (meters)
A = Cross-sectional area (m²)
Capacitance Relationships
Q = CV, E = ½CV², Xc = 1/(2πfC)
Where:
Q = Charge (coulombs)
C = Capacitance (farads)
V = Voltage (volts)
E = Energy (joules)
Xc = Capacitive reactance (ohms)
f = Frequency (hertz)

🔧 Real-World Applications

🏠
Home Electrical Systems
Calculate circuit loads, wire sizing, breaker ratings, and power consumption for residential electrical work.
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Industrial Applications
Motor calculations, transformer sizing, power factor analysis, and industrial equipment specifications.
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Battery Systems
Battery capacity calculations, charging current determination, and energy storage system design.
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Electronics Design
Component selection, circuit analysis, PCB design calculations, and signal integrity analysis.
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Power Generation
Generator sizing, transmission line calculations, and renewable energy system design.
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Education & Training
Electrical engineering coursework, technical training, and professional certification preparation.

💡 Electrical Calculation Tips

🎯 Input Guidelines

  • Unit Consistency: Always use consistent units (volts, amperes, ohms, watts)
  • Significant Figures: Consider measurement precision and round appropriately
  • Safety Margins: Include safety factors for real-world applications
  • Operating Conditions: Account for temperature, humidity, and other environmental factors
  • Code Compliance: Verify results meet electrical codes and standards

🔧 Advanced Techniques

  • AC vs DC: Remember that AC calculations may require additional considerations
  • Complex Impedance: For AC circuits, consider reactance components
  • Temperature Effects: Resistance changes with temperature (typically +0.4%/°C for copper)
  • Parasitic Elements: Real components have parasitic resistance, inductance, and capacitance
  • Frequency Response: Component behavior varies with frequency

❓ Frequently Asked Questions (FAQ)

How accurate are these electrical calculations?
Our electrical calculator uses standard engineering formulas and provides results accurate to the precision of your input values. For critical applications, always verify calculations and consider real-world factors like component tolerances and environmental conditions.
Can I use this calculator for AC circuits?
The basic calculations apply to both AC and DC circuits, but AC circuits may require additional considerations like reactive components (inductance and capacitance), power factor, and RMS values. For complex AC analysis, consider using specialized AC circuit analysis tools.
What if I only know two electrical values?
That's perfect! Ohm's law and power formulas allow you to calculate unknown values when you know at least two parameters. Enter the known values, and the calculator will determine the missing parameters automatically.
How do I account for temperature effects on resistance?
The resistance calculator includes temperature compensation. For most conductors, resistance increases with temperature. Copper has a temperature coefficient of approximately +0.393%/°C at 20°C. Enter the operating temperature for accurate results.
What's the difference between power and energy?
Power (watts) is the rate of energy consumption, while energy (watt-hours) is the total amount consumed over time. Power = Energy ÷ Time. For example, a 100W bulb running for 10 hours consumes 1000Wh (1kWh) of energy.
Can this calculator help with wire sizing?
Yes! Use the resistance calculator with wire specifications (length, cross-sectional area, material resistivity) to determine voltage drop and current capacity. Always consult electrical codes for proper wire sizing and safety requirements.
How do I calculate three-phase power?
For balanced three-phase systems: P = √3 × V × I × cos(φ), where V is line voltage, I is line current, and cos(φ) is the power factor. For three-phase reactive power: Q = √3 × V × I × sin(φ).
What safety considerations should I keep in mind?
Always follow electrical safety practices: turn off power before working, use proper PPE, verify calculations with qualified personnel for critical applications, and ensure compliance with local electrical codes. These calculations are for design purposes - always prioritize safety.
How do I convert between different electrical units?
Common conversions: 1 kW = 1000 W, 1 mA = 0.001 A, 1 kΩ = 1000 Ω, 1 µF = 1×10⁻⁶ F. Always ensure unit consistency in calculations. The calculator displays results in standard units (volts, amperes, ohms, watts).
Can I use this for motor calculations?
Basic motor power calculations are supported, but motors have additional considerations like starting current, efficiency, power factor, and slip. For comprehensive motor analysis, consult motor manufacturer data and specialized motor calculation tools.

ℹ️ About This Electrical Calculator

Our Electrical Calculator is a comprehensive tool designed for electrical engineers, technicians, students, and professionals working with electrical systems. It provides accurate calculations for fundamental electrical parameters using industry-standard formulas.

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Why Choose Our Calculator
Professional-grade accuracy, comprehensive coverage of electrical calculations, user-friendly interface, and educational value for learning electrical engineering principles.
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Professional Applications
Suitable for electrical design, circuit analysis, component selection, troubleshooting, and educational purposes in academic and professional settings.
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Privacy & Security
All calculations are performed locally in your browser. No data is transmitted or stored on our servers, ensuring complete privacy of your electrical design calculations.
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Cross-Platform
Works perfectly on desktop computers, tablets, and smartphones. Access your electrical calculations anywhere, anytime, with full functionality on all devices.
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Always Free
No registration required, no hidden fees, no limitations. Our electrical calculator is completely free to use for all your electrical engineering calculation needs.
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Educational Resource
Perfect for students learning electrical engineering, professionals updating their skills, and anyone needing reliable electrical calculations with educational explanations.

Disclaimer: While we strive to ensure the accuracy of all electrical calculations, this tool is provided for general engineering and educational use. For critical electrical installations, safety systems, or commercial applications, please verify results with qualified electrical engineers and ensure compliance with applicable electrical codes and standards.