Physics

Ohm's Law

What is the Ohm's Law?

Voltage equals current times resistance

This formula is widely used in physics applications. Understanding when and how to apply it helps you interpret calculator results correctly and catch input errors before they propagate.

Formula

V = I * R

Substitute known values into the formula above. Ensure all variables use consistent units before calculating.

Worked Example

12V, 4 ohms gives 3A

Use the linked calculator below to try your own values and see step-by-step working.

When to Use This Formula

Apply the Ohm's Law when you need to voltage equals current times resistance. It is a standard reference in physics coursework, professional practice, and our linked calculators.

Tips & Common Mistakes

  • Use SI units: kg, m, s, N, J.
  • Attach units to every number in your calculation.
  • Always verify critical results independently for engineering, medical, or legal applications.

Related Calculators

Ohms Law Calculator

Use online tool

Further Reading

Browse the Formula Library for related formulas, or read educational articles on our Blog.