# S&P 500 Dividend Reinvestment Return Gain Calculator

Use this calculator to compute the percent gain for returns associated with dividend reinvestment compared with returns associated without dividend reinvestment for the S&P 500. Starting with the January price of a used-defined starting year, the calculator computes the returns with dividend and without dividend reinvestment given the current year monthly price. It then computes the percent gain with dividend reinvestment using the following formula:

Percent Gain = (Return with dividend reinvestment - Return without dividend reinvestment / Return without dividend reinvestment) * 100

It then computes the Percent Gain for each succeeding year beginning with the January price and ending with one year before the current year. With each succeeding year the number of years held increases by one.

The percent gain in returns with dividend reinvestment will always be greater than zero meaning that dividend reinvestment outperforms returns without dividend reinvestment. The magnitude of a gain increases as the years held increases.

The calculator uses S&P 500 inflation-adjusted monthly price data from ONLINE DATA ROBERT SHILLER. Prices used by the calculator are from January 1871 through the present.