How to read Voltagelevel of the Battery ?

Using Arduino Motors, Mechanics, Power and CNC
3

I assume that there is no way without a voltage divider ?
If I have 12 V, can I use a 10K/150K voltage divider (a factor of 16) ?

The Code would look like this then ?

float batt_volt = analogRead (pin) * 80.0 / 1024 ;