Ohm's Law Calculator
V=IR — solve for any variable
Quick Answer — Ohm's Law
The Ohm's Law Calculator is a free online engineering tool that helps you v=ir — solve for any variable. Enter your values above for instant, accurate results — no signup required. All calculations run privately in your browser.
Maintained by: Sagar Sahni, Calc Labz | Review: formula checks, worked examples, and periodic updates
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Interactive Diagram
Ohm's Law circuit diagram
Step-by-Step Formula Derivation
Mathematical derivation for the Ohm's Law Calculator
Applicable Standards & Codes
Engineering standards referenced by the Ohm's Law Calculator
Engineering Reference
Learn the theory behind the Ohm's Law Calculator
Ohm's Law is the foundational principle of electrical engineering, discovered by Georg Simon Ohm in 1827. It establishes a linear relationship between voltage (V), current (I), and resistance (R) in a conductor. The law states that current flowing through a conductor is directly proportional to the voltage applied across it and inversely proportional to its resistance, expressed as V = IR.
This relationship holds for "ohmic" conductors — materials where resistance remains constant regardless of the applied voltage. Common examples include most metals and alloys at constant temperature. Non-ohmic devices like diodes, LEDs, and transistors have non-linear V-I characteristics and require more complex models.
Formula & Worked Example
The math behind the Ohm's Law Calculator
Mathematical Formula
Result = F(x_1, x_2, \dots, x_n)Step-by-Step Worked Example
Frequently Asked Questions
Common questions about the Ohm's Law Calculator
What is the Ohm's Law Calculator?
How do I use the Ohm's Law Calculator?
Is my personal data saved when using this calculator?
Can I use the Ohm's Law Calculator on my mobile phone?
How accurate is the Ohm's Law Calculator?
What is the Ohm's Law Calculator?
The Ohm's Law Calculator is a free online engineering tool that helps you v=ir — solve for any variable. Built for accuracy and speed, this calculator uses verified formulas and provides instant results without requiring any signup or registration. All calculations run entirely in your browser, ensuring complete privacy — no personal data is ever sent to our servers.
How to Use the Ohm's Law Calculator
- Enter Voltage (V) — 0 to solve: Enter your voltage (v) — 0 to solve (in V) in the input field. The calculator will validate your input automatically.
- Enter Current (I) — 0 to solve: Enter your current (i) — 0 to solve (in A) in the input field. The calculator will validate your input automatically.
- Enter Resistance (R) — 0 to solve: Enter your resistance (r) — 0 to solve (in Ω) in the input field. The calculator will validate your input automatically.
- View Your Results: The Ohm's Law Calculator displays your results instantly in the output panel. You will see the primary result along with a detailed breakdown of secondary outputs. Scroll down for charts, interpretations, and expert advice.
Key Features
- Instant Ohm's Law calculations with real-time updates
- No signup, no registration — 100% free forever
- All calculations happen in your browser — zero data sent to servers
- Works offline as a Progressive Web App (PWA)
- Mobile-friendly responsive design
- Verified engineering formulas updated for 2026
Why Use Calc Labz Ohm's Law Calculator?
The Calc Labz Ohm's Law Calculator stands out because it combines accuracy with simplicity. Unlike other online calculators, we provide detailed breakdowns, step-by-step formulas, and actionable advice alongside your results. Our engineering calculators are regularly updated to reflect current rates, rules, and standards for India (2026). Whether you are a student, professional, or just need a quick calculation — Calc Labz delivers reliable results instantly.
Key Terms & Glossary
- Ohm's Law
- V = I × R — Voltage equals Current times Resistance. The fundamental law of electrical circuits.
- Power Factor
- The ratio of real power to apparent power in an AC circuit, ranging from 0 to 1.
- Torque
- A rotational force measured in Newton-meters (N·m) that causes an object to rotate about an axis.
- Reynolds Number
- A dimensionless quantity predicting whether fluid flow is laminar (smooth) or turbulent.