If you invested $1 a day, starting when you were born

This is why all the retirement advice is to regularly contribute - Smaller amounts monthly (or even more frequently) works way better than only doing so when you're flush. The key to this is not spending all the dollars you make on your present lifestyle, but setting aside some percentage for investment from every paycheck. This means you'll be buying in the down times too, where everything is on sale.

Of course it also means accepting a lower spending rate in one's life.

Nice comparison! I feel the same about my education, pays back about my total investment every couple of months. Of course in my country (Netherlands) I pay back a lot more in taxes.

Investment fees were high more than 25 years ago. I remember paying 3% to buy or sell a stock in the 1980s when you had to use brokers. That limited the kind of day trading strategies you could use. Its as little as a hundredth of a percent now for a large computer executed transaction.

Hey guys... I made the page. Just saw lots of traffic coming from here so figured I'd come check it out.

A couple things I figured I should address after reading the comments:

1) Yahoo!'s historic S&P 500 data does not factor in dividends. So the returns would likely be 1-2% higher each year (which over time makes a very big difference). I should probably add a note on the page mentioning this.

Here was my conundrum when making the tool: I picked the S&P 500 because it's the only index that allowed me to pull very, very old data (nearly 70 years) using Yahoo! Finance; plus, it's often the "go-to" index for discussing overall market performance. But it's not "real" in the sense that you can't actually buy shares, and it doesn't pay dividends. So I could make up my own method for factoring in dividends, but I wanted to go strictly by the numbers. When you factor in financial advisor fees / bad decisions that new investors make, it's probably enough to "counter" the lack of dividends, if you want to look at it that way.

Plus, sites / companies are notorious for over-stating how much you can get annually by investing. I'd prefer to under-state it, if anything. Don't want to sell false hopes.

2) Regarding incremental, small deposits (and potential transation fees)... it's actually very easy to set up auto-investments in index funds that match the S&P 500 without ever incurring any fees. You could do $31 on the first of every month and basically simulate this.

3) Inflation would be useful to factor in, but it would also add confusion. This could be a cool add-on, but I'd have to think about the clearest way to demonstrate it. So would the 1950 daily amount be equivalent of $1 today? (so I'm guessing 20 cents or so?)

Hope you guys enjoy the site. Feedback is great (positive or negative - I'm not sensitive).

This also ignores the fact that your average person, until more recently, couldn't so easily invest in the S&P 500, without some big transaction costs. A couple of factors that make this possible today:

1. Online brokers, starting in late 90s, lowered retail trading fees, made access easier. 2. low-fee, highly liquid, highly competitive ETFs give anyone cheap exposure to the broader market indicators, like S&P 500.

So an ROI calculation from the 1970s is mostly academic, but I guess illustrative of what you might be able to get using that same approach over the next 30-40 years.