Also called: claiming at 62, actuarial reduction
Claiming Social Security before full retirement age permanently reduces the monthly benefit: 5/9 of 1% per month for the first 36 months early and 5/12 of 1% for each month beyond that.
With a full retirement age of 67, claiming at 62 is 60 months early: 36 months x 5/9% = 20%, plus 24 months x 5/12% = 10%, for a 30% permanent reduction. The reduction also lowers the base on which future cost-of-living adjustments are applied.
The reduction applies to your own retirement benefit. Spousal and survivor benefits have their own early-claiming schedules.