DC Ohm’s Law Calculator
Calculate current and dissipation for an ideal resistor at a given DC voltage.
Your result
EVERYDAYEnter your values and select calculate.
On this page How it works & practical examples
How to use the DC Ohm’s Law Calculator
Use the voltage across one ideal resistive load. The model describes a constant DC operating point, not the full behavior of a motor, LED or reactive AC load.
The calculation
Worked example
12 V across 6 ohms gives 2 A and 24 W of ideal resistor dissipation.
Assumptions and limits
Does not determine wire sizes, protective devices or safe power ratings. Resistance must be positive and is assumed constant with temperature.
Common questions
Which inputs should I use?
Use the voltage across one ideal resistive load. The model describes a constant DC operating point, not the full behavior of a motor, LED or reactive AC load.
What does the result exclude?
Does not determine wire sizes, protective devices or safe power ratings. Resistance must be positive and is assumed constant with temperature.