Ohm's Law
Solve V = I × R — enter any two of voltage, current, and resistance to find the third
About this calculator
The Ohm's Law Calculator helps you find voltage, current, or resistance when you know the other two values. Based on the fundamental formula V = I × R, this tool is essential for electronics, circuit design, and physics coursework. Enter any two values to instantly calculate the missing third.
How to use the Ohm's Law calculator
- Enter the quantities you know, using the units shown on each field.
- Read the computed results — they update instantly as you type.
- Use the visual explanation to see how the quantities relate.
- Copy the page URL to share the exact calculation.
Common examples
- V = 5 A × 10 Ω = 50 V
- I = 120 V ÷ 60 Ω = 2 A
- R = 9 V ÷ 0.3 A = 30 Ω
- V = 0.5 A × 220 Ω = 110 V
- I = 12 V ÷ 4 Ω = 3 A
Frequently asked questions
How does the Ohm's Law calculator work?
Enter the known quantities and the calculator applies the governing physical law or scientific formula to find the unknowns, stating the equation it used and the units of every result. Computations run at high precision.
When would I use the Ohm's Law calculator?
It suits physics and chemistry homework, lab work, engineering estimates, and any time you want to explore how changing one quantity affects the others in a well-defined scientific relationship.
How accurate are the results?
The formula itself is evaluated at 30 significant digits of precision. Keep in mind that idealized models — such as neglecting friction, air resistance or measurement error — bound the real-world accuracy more than the arithmetic does.
Can I share a specific calculation with someone else?
Yes. Every value you enter updates the URL, so copying the address bar and sharing the link reopens the exact same calculation for whoever clicks it.