The pension is computed from the average of your highest three years' salary (called the "hi-3"). Multiply your years of federal service times hi-3, times .01 and that will give you an idea of what your pension will be, though it's more with over 30 years' service and so on. (You can find more info on that on opm.gov .) You are vested in your pension after a few years (I've forgotten if it's 3 or 5 years). As you can tell, your pension may be pretty tiny.
The TSP is the federal equivalent of a 401K. You get 5% match. Most of your retirement will be TSP and not pension.
I see GoodSense you are only 30 - another option you may want to consider if you are thinking of going federal and want to retire early is trying to get into a 6C Law Enforcement Retirement position -
6C Law Enforcement Offices/Agents can retire at age 50 with 20 years or at any-age with 25 years.
Under 6C, the FERS pension is calculated at 1.7% * Hi-3 annual salary * 20 years. (rather than normal FERS calculation of 1%) Under 6C, any additional years you accumulate over (or before) your twenty 6C years are calculated at the normal FERS 1% including any military years you buy-back.
You can retire at age 50 with 20 years & immediately begin receiving the FERS pension + a Special Retirement Supplement (SRS - an extra payment that approximates a portion of what you will receive in Social Security when you are 62 - the SRS goes away at 62 & you start getting SS).
The FERS pension is immediately eligible for annual COLA if you retire 6c (but not the SRS) The SRS is not means-tested till you are 56 - from 56 to 62 it can be reduced $1 for every $2 you earn over 13K.
You can contribute up to $15.5 K each year into your Thrift Savings Plan (TSP) & govt will match 5%.
If you retire in the year you turn 55 you can begin TSP withdrawals without the 10% penalty.
If you retire before the year you turn 55, however, any TSP withdrawals before age 59.5 are subject to the 10% penalty UNLESS: you either
- buy an annuity (usually a bad idea);
- take "substantially equal monthly payments based on life expectancy" (SEMPLE);
- or roll it all over to a private IRA & use IRS rule 72T to take the SEMPLE.
Most Federal Criminal Investigators (Series 1811) are eligible throughout their careers for LEAP Pay (Law Enforcement Availability Pay) - this is an automatic 25% pay boost & the idea is that you will work at least 25% extra hours on call-outs, extended surveillance, etc - if you are an 1811 this is practically guaranteed, but you will likely receive little if any other type of overtime compensation. Good thing is that LEAP pay counts for your Hi-3 annuity calculation.
Some other Federal Law Enforcement positions get AUO (Authorized Uncontrollable Overtime) - this can be from 10% to 25% depending on your duty position and is usually 25% - it works about the same way LEAP does. (Border Patrol has always gotten this)
Some Federal Law Enforcement Positions get neither LEAP nor AUO - but usually those positions receive some (or substantial depending on the agency) regular time-and-a-half overtime.
Most positions (whether secretary, teacher, or correctional officer) inside a federal correctional institution where you will have contact with inmates is covered under 6C retirement.
Air Traffic Controllers & Federal Firefighters have a similar system to 6c.
Be careful when considering jobs though - there are some "law enforcement" positions that do NOT get the 6C retirement.