Reference

Guides

Short, checkable explanations of the concepts the calculators rely on. Written to be read once and then not needed again.

The one adjustment that turns an impressive projection into a number you can plan with.

Why your early payments barely touch the balance, and what follows from that for refinancing and overpaying.

The most quoted number in retirement planning, and the four things that break it.

Vanguard's data across three markets, and why the losing strategy is sometimes still the right one.

How to read a match formula, and the three fine-print details that decide whether you keep the money.

One method is always cheaper. The other is sometimes right anyway. How to tell which applies to you.