What is formula for Return On Investement?

Answer 1

(Future Value - Invested Capital) / Invested Capital.

If you need to turn that into an annualized return number it will depend on the time frame, but the general form will be to add one to the result of that equation and then raise it to ( n per year / n ), and then subtract 1.

So you get:

[1+(Future Value - Invested Capital) / Invested Capital)]^(n periods per year / number of periods) -1

That's kind of a mess. Let me give an example:

Invest: $10
Return: $12
Time: 6 months

Return on Investment:
(12-10)/10 = 0.2 = 20%

Annualized Return:
[1.2^(2/1)]-1 = 0.44 = 44%

Answer 2

Money invested = I
Money out = R
Time invested = T

Return rate = (R-I)/T