Ohm's Law Calculator
Solve V = I × R for any one variable — voltage, current or resistance.
See how it works
Watch a quick simulation of this tool in action — no file needed.
How to use Ohm's Law Calculator
Follow these steps — everything happens instantly in your browser.
- 1
Step 1. Enter any two of voltage (V), current (I) or resistance (R).
- 2
Step 2. Leave the third field empty — it is computed automatically.
- 3
Step 3. Power (P = V × I) is shown below in watts.
Why use this tool
Private by design
All processing happens locally in your browser. Open DevTools → Network and you'll see zero file uploads. Ever.
Instant
No upload wait, no queue, no server round-trip. Results appear the moment you drop a file.
Free & unlimited
No accounts, no watermarks, no daily caps. Use it as many times as you like, forever.
Works everywhere
Desktop, tablet or phone — every tool is responsive and installable as a PWA for offline use.
Frequently asked questions
Everything you might want to know about ohm's law calculator.
Resistor Color Code Calculator
Decode 4-band resistors from colors — and reverse value → colors.
Density Calculator
Solve density, mass or volume — ρ = m / V — for any two knowns.
Molar Mass Calculator
Compute the molar mass of any chemical formula — H₂O, NaCl, C₆H₁₂O₆…
pH Calculator
pH from [H⁺] and reverse — with pOH, [OH⁻] and temperature.