Not sure how much you need to save for federal retirement? A new online tool from the Office of Personnel Management helps feds figure out how to plan for how to save. It also includes projections for annuities and Thrift Savings Plan benefits.

The Federal Ballpark E$timate tool can be used by CSRS, CSRS-Offset and FERS employees, according to the OPM website.

The tool is a long-term planner, and feds within three years of retirement should contact their human resources office for a more specific annuity estimate, according to OPM.

In particular, feds early on in their careers can benefit from using the estimator. "This is because the FBE will get you thinking about how the way you save can be beneficial to you down the road to retirement. It's never too early!" according to OPM.

More federal retirement stories.