# What is the general formula for cycloalkanes?

The general formula for a cycloalkane is ${C}_{n} {H}_{2 n}$.
On the other hand, the general formula of an alkane is ${C}_{n} {H}_{2 n + 2}$. In cycloalkanes, the ring junction, the extra $C - C$ bond has reduced the hydrogen count by $2$.
Chemists speak of degrees of unsaturation with respect to organic formulae. Alkanes are conceived to be saturated, and each 2 hydrogens less than the saturated formula corresponds to a so-called $\text{degree of unsaturation}$. See here for further explanation.