Ohm’s Law Calculator

This Ohm's Law calculator works like this:

• You enter any 2 values from the 3:
  Voltage (V).
  Current (I).
  Resistance (R).
• Then hit the CALCULATE button.
• The calculator will find the missing 3rd value for you automatically.

Examples:

Example 1:

• Voltage = 12V
• Current = 2A
  Then Resistance = 12 / 2 = 6 ohms

Example 2:

• Resistance = 100 ohms
• Current = 0.05A
  Then Voltage = 100 × 0.05 = 5V

Example 3:

• Voltage = 9V
• Resistance = 3 ohms
  Then Current = 9 / 3 = 3A

Ohms Law is the most basic law of electronics. It connects the 3 main things in any electrical circuit:

• V = Voltage (in volts)
• I = Current (in amps)
• R = Resistance (in ohms)

The relation is very simple like this:

V = I × R

That means:

• Voltage is equal to Current times Resistance
• If you increase resistance, current goes down
• If you increase voltage, current goes up

You can also rearrange it like this:

I = V / R
R = V / I

Notes:

• You must enter exactly two values, not one, not all three.
• If you enter only one then it will give error.
• If you enter all three then it will use only the first two that are valid.
• Work for DC circuits or any static value.