> with an annual contribution of €13.61 and a real rate of return of 3%, 400 years of annual compounding would be over €7 million. With a rate of 4% it would be

> with an annual contribution of €13.61 and a real rate of return of 3%, 400 years of annual compounding would be over €7 million. With a rate of 4% it would be €280 million. Calculating the total return given an annual average rate of return is the easy part here. The idea that you can easily invest in a diversified basket of assets and receive a fairly safe x% a year is a relatively recent one. I'm not sure what assets you could invest in 400 years that would even be guaranteed to exist today.