Ohm's Law Calculator

Calculate voltage, current, resistance, and power using Ohm's Law. Perfect for electrical engineers, students, technicians, and electronics enthusiasts. Includes visual charts and calculation history.

About Ohm's Law

Ohm's Law is one of the most fundamental principles in electrical engineering and electronics. Named after German physicist Georg Ohm, it describes the relationship between voltage, current, and resistance in electrical circuits.

The Fundamental Formulas

  • Voltage (V): V = I × R (volts)
  • Current (I): I = V / R (amperes)
  • Resistance (R): R = V / I (ohms)
  • Power (P): P = V × I = I² × R = V² / R (watts)

Key Features

  • Multiple Calculation Modes: Calculate any value from the others
  • Power Calculations: Includes all power formula variations
  • Visual Charts: Understand relationships with interactive graphs
  • Calculation History: Track and review your past calculations
  • Export & Share: Save and share your results
  • Formula Display: Shows which formula was used for each calculation

Common Applications

  • Circuit Design: Selecting appropriate resistor values
  • Power Calculations: Determining power consumption and heat dissipation
  • Current Limiting: Calculating resistors for LEDs and other components
  • Wire Sizing: Ensuring wires can handle required current
  • Troubleshooting: Diagnosing circuit problems and failures
  • Safety: Ensuring circuits operate within safe parameters

Tips for Accurate Calculations

  • • Always use consistent units (volts, amperes, ohms, watts)
  • • Remember that resistance cannot be zero (would cause infinite current)
  • • Consider power ratings when selecting components
  • • Account for voltage drops in long wire runs
  • • Use appropriate safety margins in real-world applications

Ohm's Law FAQs

Have more questions? Contact us

What Our Users Say

5.0
Based on 1,563 reviews

This Ohm's Law calculator is a lifesaver for my circuits class! The multiple calculation modes and clear formulas make it easy to verify my homework. The visual charts help me understand the relationships better.

R
Robert Jackson
Electrical Engineering Student
October 16, 2025

I use this calculator daily in my repair work. It's fast, accurate, and the power calculation options are especially useful. The history feature helps me keep track of different circuit calculations.

L
Lisa Patel
Electronics Technician
October 11, 2025

Perfect tool for my hobby projects! The calculator handles all the variations of Ohm's Law I need, and the explanations in the FAQs helped me understand the concepts better. Highly recommend!

J
James Wilson
DIY Electronics Enthusiast
October 7, 2025

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