# 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.

Enter the two known values

Voltage U in volts
Current I in amperes
Resistance R in ohms
Leistung P in Watt

Decimal places

## 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.

### Calculate voltage

$$\displaystyle U=R · I$$
$$\displaystyle U=\sqrt{P · R}$$
$$\displaystyle U=\frac{P}{I}$$

### Calculate current

$$\displaystyle I=\sqrt{\frac{P}{R}}$$
$$\displaystyle I=\frac{U}{R}$$
$$\displaystyle I=\frac{P}{U}$$

### Calculate resistance

$$\displaystyle R=\frac{P}{I^2}$$
$$\displaystyle R=\frac{U^2}{P}$$
$$\displaystyle R=\frac{U}{I}$$

### Calculate electrical power

$$\displaystyle P=U · I$$
$$\displaystyle P=I^2·R$$
$$\displaystyle P=\frac{U^2}{R}$$