Where does the Rule of 72 come from?

JLP’s post on the Rules of 72, 114, and 144 got my math juices flowing. Where does the Rule of 72 come from? If you’re not into math, no biggie, but you might experience a little boredom. 😉 Say I have starting principal Ps with periodic interest rate r (expressed as a decimal). I let … Read more

Shopping, and reselling, for a living

EBay has turned a lot of people into resellers and virtual store owners. If you can fill out online forms and use a web-based or downloaded listing program, you can sell stuff on eBay. Now, actually turning a profit isn’t quite that easy. And making a living at it is more difficult still. This article … Read more

A really simple retirement formula

There was a discussion over in the Money Blog Network Forums about different ways to calculate how much to save to allow a particular monthly payment during retirement. Some people responded with future value and present value functions and the 4% retirement rule. These are perfectly legitimate ways of estimating what you’ll need in retirement. … Read more