Investment calculator

Most compounding interest calculators on the web only calculate a fixed amount of principal money that grows at a fixed interest rate over a certain time.

Well I found a calculator that also includes the effect of annual contributions.

However, that is still far from accurate from real investing. Because contributions may not be the same amount every time, interest rates change, the way they calculate interest can be different, prices for items go up and down, government money is always subject to huge inflation (are we talking real interest rates here or nominal interest rates?....).

Compounding interest is probably the worst way to make money but if you have no money to begin with it's probably your only choice.