How much a person can earn while on Social Security depends upon his age during a specific year. If a person is under retirement age, the limit for earnings is $15,720 in 2015. Individuals who have reached retirement age have a limit of $41,880 in 2015.
Individuals can earn more than the annual limit while on Social Security, but their benefits are reduced depending on how much they earn over the annual limit. Those who have not reached retirement age have $1 deducted from their Social Security checks for every $2 that is earned. Social Security recipients who are retirement age have $1 deducted for every $3 earned.