Complications of circumcision is rare in large series. It has been reported 1-2%.  Most of the patients in these series are under one month old (neonate). Neonates have low complication rate after circumcision as compare to older children. Complications in circumcision for older than one year old children reported more than 6% in the recent series. 

A 'snip' in time: what is the best age to circumcise?

BMC Pediatrics 2012 DOI: 10.1186/1471-2431-12-20

Infancy presents the best age for circumcision. It is associated with substantially lower costs, lower risk of complications when performed by an experienced operator in a clinical or other appropriate setting, and lower lifetime risk of a variety of adverse conditions and infections

Complications of circumcision in male neonates, infants and children: a systematic review.

BMC Urol. 2010 Feb 16;10:2. doi: 10.1186/1471-2490-10-2

Review found a median complication frequency of 1.5% among studies of neonatal or infant circumcision, compared to 6% among studies of children aged one year or older