# Calculate U, R, I and P online

Online calculator for calculating voltage, current, resistance and power

## Calculate Ohm's law and power online

To calculate the voltage U , the current I , the resistance R or the power P two of the values must be known.

Online calculator U, R, I and P

 Enter two of the four values U   Voltage µV mV V kV I   Current µA mA A kA R   Resistance mΩ Ω kΩ MΩ P   Power µW mW W kW MW GW Decimal places 0 1 2 3 4 6 8 10

## Ohm's law and power

Ohm's law is a basis of electrical engineering and electronics. It indicates the relationship between voltage, current and electrical resistance. The law says that the voltage is equal to the current multiplied by the resistance.

 Voltage $$\displaystyle U=R · I$$ $$\displaystyle U=\sqrt{P · R}$$ $$\displaystyle U=\frac{P}{I}$$ Current $$\displaystyle I=\sqrt{\frac{P}{R}}$$ $$\displaystyle I=\frac{U}{R}$$ $$\displaystyle I=\frac{P}{U}$$ Resistance $$\displaystyle R=\frac{P}{I^2}$$ $$\displaystyle R=\frac{U^2}{P}$$ $$\displaystyle R=\frac{U}{I}$$ Power $$\displaystyle P=U · I$$ $$\displaystyle P=I^2·R$$ $$\displaystyle P=\frac{U^2}{R}$$