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About Ohm's law calculator
Solve Ohm’s law for voltage, current, resistance, or power from any two known values — offline DC calculator.
V = I × R and P = V × I (with the usual rearrangements) still cover a huge share of quick electronics checks. This page lets you fill any two knowns and derives the rest so you are not rearranging algebra on scrap paper next to a breadboard.
It is DC Ohm’s law teaching math — not a full AC phasor tool, not a SPICE simulator, and not a substitute for reading a datasheet’s limits. Enter volts, amps, ohms, or watts in the fields you know; read the computed others.
Resistor color code decodes band colors to ohms; pair it when you are staring at a physical resistor. Scientific calculator is general math. Subnet calculator is networks, not circuits.
How to use Ohm's law calculator
- 1Enter any two of voltage, current, resistance, or power.
- 2Read the derived values from Ohm’s law and power relations.
- 3Clear fields to solve a different pair.
What it won't do
- DC Ohm’s law only.
- No temperature coefficients or non-ohmic devices.
Common questions
Does Ohm’s law calculator handle AC circuits?
No. It is the basic DC relationship. Reactive AC needs impedance and phase — use a proper AC tool or textbook method.
What if I fill more than two fields?
Use two knowns as inputs. Extra conflicting values mean you should clear the unknowns you want computed.
Is power included?
Yes — power ties in through P = V × I (and related forms) when the inputs allow it.
Related tools
Why this one doesn't upload your file
There is no server to upload to. This page is a static file, and the work happens in your browser using the same graphics and WebAssembly code that renders every other site you visit. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network entirely and it keeps working. The longer explanation