Electronics
Ohm’s Law Calculator
Solve Ohm’s law instantly: provide any two values (voltage, current, resistance) and the third is calculated automatically.
Solve for voltage, current, or resistance instantly.
Ohm’s law
V = I × R
Rearranged forms compute current (I = V ÷ R) or resistance (R = V ÷ I). Power is also shown using P = V × I.
How to use
- Select which value to solve for.
- Enter the known quantities using volts, amps, and ohms.
- Read the solved value plus instantaneous power and unit-scaled outputs.
Example
Input: Solve for current: Voltage = 12 V, Resistance = 4 Ω
Output: Current = 3 A, Power = 36 W
Student-friendly breakdown
This walkthrough emphasizes the most searched ideas for Ohm’s Law Calculator: ohms law calculator, voltage current resistance calculator, ohms law chart, ohms law calculator with power. Start with the formula above, then follow the guided steps to double-check your work. For quick revision, highlight the givens, plug into the equation, and finish by verifying your units.
Need more support? Use the links below to open the long-form guide, browse additional examples, or hop into adjacent calculators within the same topic — each one is a quick way to double-check your work or handle a related question without starting from scratch.
Deep dive & study plan
Ohm’s Law Calculator: Solves for voltage, current, or resistance in DC circuits. It's built around ohms law, voltage, current, so you can go from a raw question to a checked answer without switching tools.
The math behind it: Rearranged forms compute current (I = V ÷ R) or resistance (R = V ÷ I). Power is also shown using P = V × I. The core relationship is V = I × R, shown above the calculator so you can see exactly how your inputs turn into the result.
To use it well: (1) Select which value to solve for. (2) Enter the known quantities using volts, amps, and ohms. (3) Read the solved value plus instantaneous power and unit-scaled outputs. Keep your units consistent as you go, and re-run a case you already know the answer to — it's the fastest way to catch a typo before it throws off a result you're relying on.
Worked example: entering Solve for current: Voltage = 12 V, Resistance = 4 Ω returns Current = 3 A, Power = 36 W. Try swapping in your own numbers next, especially a case you're unsure about, before you use this for something that matters.
Quick retention checklist
- Speak the formula aloud (or annotate it) so the relationships stick.
- Write each step in your own words and compare with the numbered list above.
- Swap in new numbers for the Example to make sure the calculator (and your logic) handles edge cases.
- Check at least one related calculator below — it's the fastest way to confirm your numbers still line up from a different angle.
FAQ & notes
Can I use milliamps or kilohms?
Yes—pick alternate units from the select inputs and the calculator handles conversions internally.
Does it support AC impedance?
This tool focuses on DC circuits. Use the Power Factor calculator for AC efficiency considerations.
What formula does the Ohm’s Law Calculator use?
Rearranged forms compute current (I = V ÷ R) or resistance (R = V ÷ I). Power is also shown using P = V × I.
How do I use the Ohm’s Law Calculator?
Select which value to solve for. Enter the known quantities using volts, amps, and ohms. Read the solved value plus instantaneous power and unit-scaled outputs.