Substantial Gainful Activity (SGA) is significant work with gross earnings that meet a threshold amount set by Social Security that is adjusted each year. The monthly SGA amount for 2019 is $1,220.

2009 $980
2010 $1000
2011 $1,000
2012 $1,010
2013 $1,040
2014 $1,070
2015 $1,090
2016 $1,130
2017 $1,170
2018 $1,180
2019

$1,220

The annual adjustments for SGA can be found at https://www.ssa.gov/oact/cola/sga.html.