Interest, and why time is doing the work — the deck

An activity. What time does to money. Fifty dollars a month at seven percent average annual growth, starting at eighteen.
After ten years, about eight thousand six hundred dollars. You have paid in six thousand of that.
After twenty years, twenty six thousand. You have paid in twelve thousand.
After thirty years, sixty one thousand, against eighteen thousand paid in. Notice that the gap between what you put in and what you have is now larger than what you put in.
And at sixty five, forty seven years of it, about two hundred and nineteen thousand dollars.
You would put in about $28,200 and finish near $219,321. Roughly $191,121 of that was never your money, it is growth. Change the amount and the starting age on the practice page and watch the last figure move.