Ohm's law — common cases, pre-computed
The current (I = V/R) and power (P = V²/R) for the most common voltage / resistance combinations. Need a different value? Open the interactive calculator.
5V across…
9V across…
12V across…
24V across…
3.3V across…
Values are reference estimates using ideal Ohm's law — real components have tolerance and self-heating; confirm against the datasheet.