![[USGS Home Page]](/visid-icons/c_168_USGS.gif){kind=icon}
This page contains a list of technical details related to the USGS TSP Calculator. You do not need to know these details in order to use the program, but if you are the type that likes to use spreadsheets and such this information might be useful to you.
In this program all actions are effective on the first day of the month. If (for example) you have an interfund transfer from the C fund to the G fund effective "5/2008" that transfer will be effective on May 1, 2008. There is no way to make actions effective during any other part of the month.
Interest to all accounts is accrued on the last day of the effective month. This means that if you change the percent return rate of the G fund from 5% to 6% effective 9/2007 using an Action (which is effective at the beginning of the month) the G fund will accrue interest at the new 6% rate for the entire month of September. In addition, interest does NOT accrue for contributions added to your account during the month.
All contributions (including Government matching for FERS employees) are added to an account at the end of the month they are effective. Therefore if you change your overall amount contributed to TSP using an Action, that change will be affect contributions for the entire first month of the Action.
No adjustments for inflation are made in this program. All calculations and interest are done on the value of the dollar at the time of calculation. If your TSP estimate shows an account balance of $500,000 when you retire in 2015, that $500,000 is in current not constant dollars and will not accurately reflect the buying power of $500,000 in the future. In other words, $500,000 will probably not buy as much in 2015 as it does in 2004.
There are several obvious differences between this calculator and the one available at the TSP website, specifically:
| Item | tsp.gov | USGS TSP Calculator |
|---|---|---|
| Calculates interest based on a single rate of return | Yes | Yes |
| Automatically calculates government matching contributions for FERS employees | Yes | Yes |
| Calculations based on "current" not "constant" dollars | Yes | Yes |
| Calculates interest based on the rate of return of each fund | No | Yes |
| Can take into account promotions, WGI, and other salary increases | No | Yes |
| Allows changes in interest rates over time | No | Yes |
| Allows simulated interfund transfers | No | Yes |
| Automatically places a limit on personal contributions that exceed the IRS annual maximum | No | Yes |
| Allows you to calculate the effects of "Catch-up" contributions on your TSP balance | No | Yes |
In addition, the tsp.gov calculator calculates monthly interest based on 50% of that month's contributions. The USGS TSP Calculator does not include current month contributions in the interest calculation. As a result account estimates in tsp.gov will generally be higher than estimates from the USGS TSP Calculator by approximately one-half's month interest on identical data.
If you have any questions about any of the information provided on this site, please contact the HRWebmaster.