How is the Value of the SP500 Calculated?

How is the Value of the SPX calculated

Free-Float Market Capitalization Methodology

S&P details the mathematical calculations of its free-float market capitalization methodology to lend transparency to its reporting value.

The calculation for the S&P 500 is:

$\begin{aligned} &\text{Index Level} = \frac { \sum_{i = 1}^n P_i \times Q_i }{ \text{Divisor} } \\ &\textbf{where:} \\ &P_i = \text{Price} \\ &Q_i = \text{Free-float shares} \\ \end{aligned}$