Aisha K.
Mar 12, 2026
Clean layout and the results update instantly. Exactly what I needed for a quick planning check.
Unit Converters
Ohm’s Law Converter — Volts, Amps, Ohms
V = I R; I = V / R; R = V / I; P = V I = I² R = V² / R.
V = I × R. Enter any two, solve the third. Power is V × I. This is DC or RMS-with-a-straight-face. Reactance, power factor, and a warm resistor are not fields.
Ohm’s law
DC / RMS
12 V
Power is V × I. Reactance is not in the fields.
- Voltage
- 12 V
- Current
- 2 A
- Resistance
- 6 Ω
- Power
- 24 W
Plain-English guide
Terms & how it works
Confused by a field? Read the short definitions here while you use the tool.
Known values
The “Known values” value used in this tool’s formula. Adjust it to see results update live.
How this calculator works
V = I × R. Enter any two, solve the third. Power is V × I. This is DC or RMS-with-a-straight-face. Reactance, power factor, and a warm resistor are not fields. V = I R; I = V / R; R = V / I; P = V I = I² R = V² / R. Example: 12 V across 6 Ω → 2 A, 24 W. 5 V, 20 mA LED math is a different, kinder page.
V = I R; I = V / R; R = V / I; P = V I = I² R = V² / R.
Example: 12 V across 6 Ω → 2 A, 24 W. 5 V, 20 mA LED math is a different, kinder page.
When to use this Volts Amps Ohms
Common use cases
- V = I × R. Enter any two, solve the third. Power is V × I. This is DC or RMS-with-a-straight-face. Reactance, power factor, and a warm resistor are not fields.
- Sanity-check with this case: 12 V across 6 Ω → 2 A, 24 W. 5 V, 20 mA LED math is a different, kinder page.
- The relationship is: V = I R; I = V / R; R = V / I; P = V I = I² R = V² / R.
Localized examples
- Unit Converters: the example on this page uses the same formula as the widget.
What you get
- Fields: Known values
- V = I R; I = V / R; R = V / I; P = V I = I² R = V² / R.
- Example on the page: 12 V across 6 Ω → 2 A, 24 W. 5 V, 20 mA LED math is a different, kinder page.
How to Convert Volts Amps Ohms Step-by-Step
- 1Enter Known values. Use the values you have, not a catalog average, unless that is all you know.
- 2V = I R; I = V / R; R = V / I; P = V I = I² R = V² / R.
- 3Worked case: 12 V across 6 Ω → 2 A, 24 W. 5 V, 20 mA LED math is a different, kinder page.
- 4Check which dictionary the other person is using — US or UK, decimal or 1,024 — then trust the number.
Governing formula
V = I R; I = V / R; R = V / I; P = V I = I² R = V² / R.
12 V across 6 Ω → 2 A, 24 W. 5 V, 20 mA LED math is a different, kinder page.
Example: set Known values = 12, then read the result.
Variable definitions
- value
Known values
The “Known values” field. Default 12; typical range 0–1000.
- The conversion (V = I R; I = V / R; R = V / I; P = V I = I² R = V² / R.) does not pick US vs UK gallons, SI vs binary megabytes, or Mach at altitude for you. Read the footnote on the page.
- Nothing here is uploaded for the calculation itself.
Frequently Asked Questions
Use RMS values and remember the wiring code. This is not a permit.
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Reviews & Ratings
See what others think about this tool, then leave your own rating to help improve CalculioHub.
4.8
out of 5.0
4 reviews
Daniel R.
Feb 28, 2026
Very usable on mobile. Would love a save/export option later, but the math feels solid.
Priya S.
Feb 3, 2026
The FAQ section answered my questions before I even had to search. Smooth dark mode too.
Marcus L.
Jan 19, 2026
Simple inputs, clear outputs. This replaced three bookmarks I used to juggle.
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