Pension Amount at 62 with only 5 years on job

I just got hired at a FERS eligible job. I know you need 5 years on the job to be eligible for a pension when you retire but let's say I'm laid off right after year 5 and then get a job outside of government without FERS until I retire at 62. When I'm 62, how would I calculate my FERS pension amount from the 5 years of service I did?