The gordon model is used to valuate the price of stocks on mature markets because those companies will have a steady performance, so you can assume the dividends of the stock will be practically constant and the growth will be constant as well.
The formula is:
Price = Dividend / ( r - g )
So, if you need the “g” rate, you must solve for g and get:
g = r - D / P
You need, of course, the other variables as given.
The other way is to use the ROE and the retention rate of dividends, i.e. the portion of net earnings that will go back to the company (dont be declared as dividend).
Example:
So if you have a net earnings of 5MM and an average net equity of 80MM you will have a ROE of 6.25%.
Then, the company’s dividend policy is to declare as dividend the 40% of the net earnings. So your retention rate is 60%. To get the “g” rate you multiply both the ROE and the retention rate: g = (6.25%)(60%) = 3.75%