Formula Voltage Divider Output voltage Input voltage Electrical resistance
$$U_{\text{out}} = \frac{R_2}{R_1 + R_2} \, U_{\text{in}}$$ $$U_{\text{out}} = \frac{R_2}{R_1 + R_2} \, U_{\text{in}}$$ $$U_{\text{in}} = \frac{R_1 + R_2}{R_2} \, U_{\text{out}}$$ $$R_1 = \left( \frac{ U_{\text{in}} }{ U_{\text{out}} } - 1 \right) \, R_2$$ $$R_2 = \frac{ R_1 }{ \frac{ U_{\text{in}} }{ U_{\text{out}} } -1 }$$
Output voltage
$$ U_{\text{out}} $$ Unit $$ \mathrm{V} $$ Output voltage is the (desired) voltage you get between the two ends of the resistor \(R_2\).
Input voltage
$$ U_{\text{in}} $$ Unit $$ \mathrm{V} $$ Applied voltage to be reduced to the value \(U_{\text{out}}\) using the voltage divider.
Electrical resistance
$$ R_1 $$ Unit $$ \mathrm{\Omega} $$ One of the two resistors used to build the voltage divider. \(R_1\) must be selected appropriately to get the desired output voltage \(U_{\text{out}}\). The larger \(R_1\) is chosen, the smaller the output voltage will be.
Electrical resistance
$$ R_2 $$ Unit $$ \mathrm{\Omega} $$ Electrical resistance of the resistor at which the resulting voltage \(U_{\text{out}}\) is present.