A. First, you will receive in the mail your social security statement once every five years from age 25 to 60 (and every year after age 60). The statement is mailed to you three months before your birthday.
If you can't wait that long, you can visit Social Security Administration's website (www.ssa.gov/myaccount/) at anytime to estimate online.
The estimate is done based on your past earnings and assume your current earning will remain the same until age 62. Of course, if your future earnings will be higher, your actual social security benefit payment will be higher (or lower if your future earnings will drop or if you retire early than age 62).
You can do a more precise (and more complicated) estimation of the social security benefit by using the "Detailed Calculator" on the SSA website.