Learn how the TSP works
Short, plain explanations. Each one names the official rule it rests on and the date it was checked.
Guides
- How TSP interfund transfers work
Two moves a month, then G Fund only; the noon Eastern cutoff; which day's price you get.
- How to read a backtest
What growth per year, worst year and biggest drop mean, why hindsight flatters every plan, and what to look at instead.
- TSP glossary
Every term this site uses, in a sentence or two.
- Methodology and data
Where the prices come from, how the engine works, and every rule with its source and date.
The tools
The backtester tests a month-by-month plan against official share prices since 2003. The strategies page lists saved plans with how each has done since it was saved. The funds page shows every fund's price and returns. The contribution planner spreads this year's contributions over your remaining pay dates without losing agency match.